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SERV1789

October 2004

TECHNICAL PRESENTATION

D8T TRACK-TYPE TRACTOR

Meeting Guide 789

(STMG)

SERVICE TRAINING

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D8T TRACK-TYPE TRACTORMEETING GUIDE 789 SLIDES AND SCRIPT

AUDIENCE

Level II Service personnel who have knowledge of the principles of machine systems operation,

diagnostic equipment, and procedures for testing and adjusting.

CONTENT

This presentation discusses the operation of the power train, the differential steering system, the

implement hydraulic system, the demand fan and the cooling systems, and the Caterpillar

Monitoring and Display System with Advisor on the D8T Track-type Tractor. Also discussed

is the operation of the controls in the operator compartment and the location and identification

of the major components of the C15 ACERT technology engine.

OBJECTIVES

After learning the information in this presentation, the serviceman will be able to:

1. locate and identify all of the major machine components;

2. locate and identify all filters, dipsticks, indicators, fill tubes, drains and test points;

3. locate and identify the major components of the C15 ACERT technology engine and

trace the flow of fuel through the C15 engine fuel delivery system;

4. trace the flow of air through the engine's air intake system;

5. trace the flow of coolant through the cooling system of the D8T;

6. identify and explain the function/operation of each component in the hydraulic demand

fan system;

7. trace the flow of oil through the hydraulic demand fan system;

8. identify and explain the function/operation of each component in the power train system;

9. trace the flow of oil through the power train hydraulic system;

10. identify and explain the function/operation of each component in the steering hydraulic

system;

11. trace the flow of oil through the steering hydraulic system;

12. explain the function/operation of each component in the implement hydraulic system;

13. trace the flow of oil through the implement hydraulic system; and14. locate and identify all the major components in the Caterpillar Monitoring and Display

System, with Advisor.

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REFERENCES

Engine Systems Operation, Testing & Adjusting (C15 &C18 Engine) . . . . . . . . . . . . .SENR9382

Engine Troubleshooting Guide (C15 &C18 Engine) . . . . . . . . . . . . . . . . . . . . . . . . . .SENR9748

Systems Operation, Testing & Adjusting (Power Train) . . . . . . . . . . . . . . . . . . . . . . .RENR7526Systems Operation, Testing & Adjusting (Hydraulic System) . . . . . . . . . . . . . . . . . . .RENR7527

Systems Operation, Testing & Adjusting (Cooling Systems) . . . . . . . . . . . . . . . . . . . .RENR8197

Schematic (Hydraulic System) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RENR7528

Schematic (Electrical) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .RENR7530

PREREQUISITES

Interactive Video Course "Fundamentals of Mobile Hydraulics" . . . . . . . . . . . . . . . .TEMV9001

Interactive Video Course "Fundamentals of Electrical Systems" . . . . . . . . . . . . . . . .TEMV9002

STMG 546 "Graphic Fluid Power Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SESV1546

SUPPLEMENTARY TRAINING MATERIALS

D8T Track-type Tractor - New Product Introduction (NPI) . . . . . . . . . . . . . . . . . . .SERV7104-09

STMG 790 "Caterpillar Monitoring and Display System, with Advisor" . . . . . . . . . . .SERV1790

STMG 736 "D8R Series II Track-type Tractor" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SESV1736

STMG 633 "D8N Track-type Tractor - Two Pump Hydraulic System" . . . . . . . . . . . .SERV1633

STMG 547 "Track-type tractor - Power Train and Implements" . . . . . . . . . . . . . . . . . .SERV1547

Technical Instruction Module "Air Conditioning Principles and Operation" . . . . . . . .SEGV2580CD ROM version of SEGV2580 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SERV2580

Technical Instruction Module "Air Conditioning Service Procedures" . . . . . . . . . . . . .SERV2581

Estimated Time: 6 Hours

Visuals: 145 Slides

Serviceman Handouts: 5 Lab Exercises

Form: SERV1789

Date: 10/04

STMG 789 - 3 - Text Reference

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TABLE OF CONTENTS

INTRODUCTION ........................................................................................................................5

OPERATOR'S COMPARTMENT................................................................................................6

CATERPILLAR MONITORING AND DISPLAY SYSTEM WITH ADVISOR .................21

Start Up .................................................................................................................................28

ENGINE......................................................................................................................................33

Fuel System...........................................................................................................................52

Engine Air System ................................................................................................................53

Cooling System.....................................................................................................................54

Hydraulic Demand Fan System ............................................................................................58

POWER TRAIN .........................................................................................................................66

Power Train Electronic Control System ...............................................................................67

Power Train Hydraulic System.............................................................................................68

Torque Divider ......................................................................................................................75

Power Shift Transmission .....................................................................................................84

Electronic Brake Control Valve ............................................................................................90

DIFFERENTIAL STEER MECHANICAL OPERATION ......................................................101

Differential Steering System Operation..............................................................................103

IMPLEMENT HYDRAULIC SYSTEM..................................................................................118

Implement System Operation .............................................................................................129

Implement Pump Operation................................................................................................131

Implement Control Valve operation....................................................................................142

Dual Tilt Operation .............................................................................................................153

Quick-drop Valve ................................................................................................................159

AutoCarry Components ......................................................................................................166

CONCLUSION.........................................................................................................................173

HYDRAULIC SCHEMATIC COLOR CODE.........................................................................174

VISUAL LIST ..........................................................................................................................175

SERVICEMAN'S HANDOUTS...............................................................................................177


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INTRODUCTION

This presentation discusses the major design features and changes, the component locations and

identifications, and the systems operation of the D8T Track-type Tractor. The D8T appearance

is similar to the D8R Series II. The operator station incorporates the common cab, which is also

used for the D9T, and the D10T Track-type Tractors.

The D8T is powered by the C15 ACERT (Advanced Combustion Emissions Reduction

Technology) electronic engine equipped with the Mechanical Electronic Unit Injection (MEUI)

fuel system. This engine also utilizes the A4 ECM engine control and is equipped with an Air

To Air AfterCooler (ATAAC) intake air cooling system. The C15 is an in-line six-cylinder

arrangement and is rated at 231.6 net kW (310 net horsepower) at 1850 rpm.

Other standard features include: power train hydraulic system with a common top pressure

strategy and remote pressure test ports, an electro-hydraulic demand fan, electro-hydraulic

steering, an electro-hydraulic implement system with easily accessible components, theAdvanced MOdular Cooling System (AMOCS) radiator, and the new Caterpillar Monitoring

and Display System with Advisor.

The D8T can also be equipped with optional attachments such as an engine pre-lubrication

system, a cold-start package, a reversing fan, dual tilt blade controls with the Automatic Blade

Assist (ABA) feature, and AutoCarry. The D8T can be ordered ready to accept the Computer

Aided Earthmoving System (CAES) and the AccuGrade system.

The serial number prefix for the D8T is KPZ, for machines built in the U.S. The serial number

prefix for the D8T built in Brazil is J8B.

1


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D8T TRACK-TYPE TRACTD8T TRACK-TYPE TRACTOROR

2004 Caterpillar Inc. 2004 Caterpillar Inc.

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2

OPERATOR'S COMPARTMENT

The operator's compartment for the D8T incorporates the "Common Cab," which is used on the

D8T, the D9T, and the D10T Track-type Tractors. The cab is eight inches wider than the cab

used for previous models. The cab has wider doors that open 20 further for easier entry and

exit. It contains more glass area for better overall visibility for the operator.

Included in the new cab design is:

- the Caterpillar Monitoring and Display System with Advisor;

- a new dash with an automotive style sealed instrument cluster;

- a new right-hand console with redesigned controls for lighting and other machine systems;

and

- electro-hydraulic implement and steering controls.


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3

The Cat contour seat is standard equipment, with air suspension available as an attachment. The

seat provides maximum comfort and less operator fatigue. The operator can adjust the seat

height, the front to rear seat position and tilt, and the seat back angle. The seat is angled 15 to

the right in order to provide maximum visibility of implement operation.

The padded left armrest is manually adjustable for height using the two knobs (1) below the

armrest The padded right armrest is similarly adjustable. Padded knee braces (2) provide

operator comfort when operating the machine on side slopes.

The back and seat cushion assembly can be removed from the suspension base by removing one8mm bolt (3), located on the lower front, center of the seat.


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Forward of the left armrest is the steering control lever, or tiller (1). The steering tiller combines

steering, directional changes, and gear selection into one control. When pulled up, the parking

brake switch (2) shifts the transmission to FIRST gear NEUTRAL and energizes the parking

brake and secondary brake solenoids on the electronic brake valve, which engages the brakes.

The parking brake switch also electronically disables the steering system and mechanically

locks the tiller housing.

FORWARD, NEUTRAL, and REVERSE are controlled by rotating the tiller hand grip (3). All

three positions have detents that hold the tiller in the selected position. A PWM rotary position

sensor connected to the hand grip provides a signal to the Power Train ECM when the handgripis rotated. In addition, a forward switch and a reverse switch are also used to signal the Power

Train ECM and confirm the hand grip position. The Power Train ECM then sends a

corresponding signal to the appropriate transmission modulating solenoid valves to engage and

disengage the forward and reverse clutches in the transmission.

The top yellow button (4) upshifts the transmission one gear range at a time, and the bottom

yellow button (5) downshifts the transmission one gear range at a time.


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Left turns are accomplished by rotating the tiller (1) toward the front. Right turns are

accomplished by rotating the tiller toward the rear. When the operator releases the tiller, a

centering spring returns the tiller to the center (NO STEER) position. Three PWM rotary

position sensors (triple redundant) are attached to the tiller shaft and send electronic signals to

the Power Train ECM regarding the tiller's position. The Power Train ECM sends acorresponding signal to the left or right proportional solenoid valves that control the steering

pump.

NOTE: The differential steering strategy still incorporates the standard "S-Turn" logic used in

previous differential steer machines.

NOTE: When the parking brake is engaged, the secondary brake solenoid is also energized, as

a backup measure.

With the engine running and the transmission shifted to NEUTRAL, rotating the steering

tiller toward the front or the rear will cause the machine to steer. The tracks will counter-

rotate, resulting in the machine pivoting about its center point. To avoid personal injury

and/or property damage, always ENGAGE the parking brake when not operating the

machine and when other personnel are nearby.


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The right console contains the implement controls and most of the controls and switches for

machine systems and functions. The dozer control lever (1) allows the operator to control all of

the blade functions with one lever.

To the rear of the dozer control lever is the ripper control handle (2). The ripper control handle

allows the operator to control all of the ripper functions. If the machine is equipped with a

winch, the winch control would be located in this same position.

Located to the rear of the ripper handle and on the vertical panel of the right console is the rear

action lamp (3), which alerts the operator of a machine system that is operating out of its normal

range. Just forward of the action lamp is a 12-volt switched power adapter (4).

To the right of the dozer control lever is the forward horn button (5).

On the vertical panel and above the forward horn button, is the key start switch (6).

Ahead of the dozer control lever is the Cat Advisor graphical display module (7), which will

be discussed in greater detail, later in this presentation.

The Machine Security System (MSS) indicator light (8) is located below the Advisor panel.


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The dozer control lever (1) allows the operator to control all of the blade functions with one

lever. When the lever is moved FORWARD, the blade will LOWER. Moving the lever forward

to a point within 3- 4 of the soft FLOAT detent causes the quick-drop valve to activate.

Moving the lever completely forward to the soft FLOAT detent activates the FLOAT function.

The lever will return to the centered position and maintain the FLOAT function. Moving the

lever either forward or rearward from the centered position will deactivate the FLOAT function.

Moving the lever to the rear of the center (HOLD) position causes the blade to RAISE. Moving

the dozer control lever to the right tilts the right side of the blade down. Moving the lever to the

left tilts the left side of the blade down.

If the machine is equipped with dual tilt, moving the thumb lever (2) to the right allows the

operator to DUMP the blade (PITCH FORWARD). Moving the thumb lever to the left will

RACK BACK the blade.

The left yellow button (3) allows the operator to activate segments in the Auto Blade Assist

(ABA) cycle and/or the AutoCarry cycle, if the machine is equipped with ABA or AutoCarry.

The right yellow button (4) cancels the ABA or AutoCarry cycle. The blade may be controlled

manually at any time during the ABA or AutoCarry cycles.


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Located on the front of the dozer control lever is the trigger switch (not shown). When

depressed and held, the trigger switch toggles between single tilt and dual tilt modes. Releasing

the trigger switch toggles back to the default tilt mode. Either single tilt or dual tilt may be set

as the default tilt mode using Cat Advisor.

The left rocker switch (5) on the panel ahead of the dozer control lever, and below the Advisor

panel is the ABA switch. It is used to arm the ABA mode. All of the Auto Blade Pitch settings

for LOAD, CARRY, and SPREAD may be configured using Cat Advisor.

The right rocker switch (6) manually activates the fan reversing cycle, if the machine is

equipped with a reversing fan.

NOTE: There are three different dozer control levers that can be installed in the D8T,

depending on how the machine is equipped.

The dozer control lever shown in illustration 6 is used on machines that are equippedwith dual tilt. Machines equipped with dual tilt also include the ABA feature.

If the machine is not equipped with dual tilt, but is equipped with AutoCarry, the control

lever will look the same, but the thumb rocker switch is not active.

If the machine has neither dual tilt nor AutoCarry (standard single tilt machine), the

dozer control lever will not include the thumb rocker switch or the two yellow buttons.


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To the rear of the dozer control lever is the ripper control handle (1). Pulling back on the left

side of the finger switch (2) moves the tip of the ripper SHANK IN. Pulling back on the right

side of the finger switch moves the tip of the ripper SHANK OUT.

At the left of the ripper control handle is the thumb switch (3), which controls RIPPER RAISE

and RIPPER LOWER. Pushing against the top of the thumb switch RAISES the ripper.

Pushing against the bottom of the thumb switch LOWERS the ripper.

Pushing the Auto-Stow button (4) raises the ripper to the maximum height and can move the

ripper tip to the full SHANK IN or full SHANK OUT position, depending on the operatorsettings configured using Cat Advisor. There are three Auto-Stow positions that may be

configured: RIPPER RAISE, RIPPER RAISE/SHANK IN, or RIPPER RAISE/SHANK OUT.

If the machine were equipped with a winch, the winch controls would be located in this same

position. The winch control is similar to that used on the current D8R Series II Track-type

Tractor, except that the drum clutch disconnect position has no detent.


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The panel on the outside of the right console contains a number of switches that control various

machine functions. To the immediate right of the key switch is the High/Low Idle switch (1).

Just above the High/Low Idle switch is the Implement Lockout switch (2), which disables

implement movement and illuminates the Implement Lockout indicator light in the instrument

cluster, when activated. Activating the Implement Lockout switch de-energizes the implement

lockout solenoid, which shuts off the flow of pilot oil to the implement control valves. With no

pilot oil available to the implement control valves, the implements cannot move.

The AutoShift Mode switch (3) activates the AutoShift mode. The AutoShift mode may beconfigured using Cat Advisor, or by using Caterpillar Electronic Technician (Cat ET).

The Auto KickDown Mode switch (4) enables the Auto KickDown mode, when activated.

Shift-point sensitivity for the Auto KickDown mode (Low, Medium, and High) may be

configured using Cat Advisor, or by using Cat ET.

If the machine is equipped with AutoCarry, the AutoCarry Mode switch (5) arms the AutoCarry

mode when activated.


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The ripper pin puller switch (6) is used to automatically retract and extend the ripper shank pin,

if the machine is equipped with a single shank ripper.

The four switches (7) at the rear of the console activate all the exterior machine lights.


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9

Located at the bottom front of the left console, and just inside the left cab door is the main fuse

panel, circuit breakers, and diagnostic connector. Opening the hinged door gains access to:

1. the air conditioning remote condenser circuit breaker (if equipped - not shown, above)

2. the HVAC blower motor circuit breaker

3. the diagnostic connector for the Cat ET

4. the 12 volt switched power supply (for powering a laptop computer or other devices)

5. the 175 amp alternator fuse

6. the main electrical fuse panel, using automotive type fuses

A fuse and breaker identification chart (7) is affixed to the inside of the hinged door. The chart

shows fuse locations and identifies their associated electrical circuits.

Several spare fuses, a spare 175 amp alternator fuse, and a fuse puller tool are also stored inside

the hinged door.

NOTE: The hinge on the door is spring loaded so that the door may be completely

removed, if necessary.


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The HVAC controls and the wiper/washer controls are located overhead, above the right

console. From left to right, these controls are:

1. HVAC blower fan speed switch, with four fan speed positions

2. HVAC temperature control

3. air-conditioning selector switch (ON/OFF)

4. front windshield wiper/washer control switch

5. left cab door wiper/washer control switch

6. right cab door wiper/washer control switch

7. rear cab window wiper/washer control switch


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The dash in the new cab contains an automotive style instrument cluster, which replaces the

quad gauge module and the main display module with mode/alert indicators of the previous

Caterpillar Monitoring System. The instrument cluster is a sealed unit that contains the

following four analog gauges:

1. hydraulic oil temperature gauge

2. engine coolant temperature gauge

3. torque converter oil temperature gauge

4. fuel level gauge

Also included in the instrument cluster is the tachometer (5) and up to fifteen indicator lights

that alert the operator of different operational modes or conditions.

The LCD display (6) below the tachometer displays the service hours at the bottom of the

display, the track speed at the upper left, and the selected transmission gear and direction at the

upper right.

INSTRUCTOR NOTE: The instrument cluster and new monitoring system will be

discussed in more detail, later in this presentation.


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Below the dash are the service brake pedal (1) and the decelerator pedal (2). The service brake

pedal applies the service brakes (both left and right) proportionately with the amount of pressure

applied by the operator. When depressed, the pedal provides a signal to the Power Train ECM

from the rotary position sensor connected to the pedal. The Power Train ECM then signals the

electronically controlled brake valve. When completely depressed, the brakes are fully engaged.

The smaller pedal on the right is the decelerator pedal. During normal operation, the machine

operates at high idle. Depressing the decelerator pedal decreases the engine rpm by a signal to

the Engine ECM from the rotary position sensor connected to the pedal.

Intermediate engine speeds are attained in the following manner. First, set the high/low idle

switch to the HIGH IDLE position, and then depress the decelerator pedal to the desired engine

speed. Then, press and hold the high idle (rabbit) side of the high/low idle switch for

approximately three seconds and then release the switch to set the intermediate engine speed.

The engine speed may then be reduced from this intermediate engine speed by depressing the

decelerator pedal. When the decelerator pedal is released, the engine speed will return to the

intermediate setting. The intermediate engine speed setting may be cancelled by pressing either

the high idle (rabbit) or low idle (turtle) side of the switch again.


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The Power Train ECM (1) and the Implement ECM (2) are located at the rear of the cab.

Accessing the Power Train ECM can be accomplished by removing the operator seat and the

sound panel at the rear of the cab. The sound panel under the right console must also be

removed to gain access to the Implement ECM. Other components located here are:

3. the J1/P1 connector for the Implement ECM

4. the J2/P2 connector for the Implement ECM

5. the J1/P1 connector for the Power Train ECM

6. the J2/P2 connector for the Power Train ECM

7. the exterior lighting relays

NOTE: The Implement ECM and Power Train ECM code plugs are tied to the wiring

harness, below the ECMs.


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CATERPILLAR MONITORING AND DISPLAY SYSTEM, WITH ADVISOR

The monitoring system for the D8T has been upgraded to the Caterpillar Monitoring and

Display System with Advisor.

The major components in the new monitoring system consist of the Advisor graphical display

module (1) and the in-dash instrument cluster (2). The graphical display module has a self-

contained ECM (Advisor ECM).

Advisor allows the operator to configure machine and implement operation and the displayoptions, then save them to an operator profile that may be selected whenever the operator

desires.

Advisor also allows the serviceman to configure certain password protected machine functions

and to view system status information for the engine, the power train, the steering, and the

implement systems. The serviceman can also perform calibrations of the machine and

implement controls, the brakes and transmission, and the steering system through the Advisor

panel.


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The Caterpillar Monitoring and Display System (CMDS) continuously monitors all machine

systems. CMDS consists of both software and hardware components. The hardware

components consist of the Cat Advisor graphical display module, a sealed instrument cluster, the

Engine ECM, the Implement ECM, the Power Train ECM, the Action Alarm, the rear Action

Lamp, and various switches, sensors, and senders. If the machine is so equipped, the CMDS

may also include connections to a Product Link ECM, a Computer Aided Earthmoving System

(CAES), and the Accugrade system and its components.

The CMDS components communicate with each other and with electronic controls on the

machines components through the Cat Data Link and through Controller Area Network (CAN)Data Links. A machine with standard equipment uses the Cat Data Link, the CAN A Data Link,

and the CAN C Data Link. With AutoCarry attachments, CMDS will also include a CAN B

Data Link (shown in dashed lines, above) and a CAN D Data Link (not shown, above).

Advisor constantly monitors all of the ECMs, the alternator R-Terminal, the system input

voltage, and the fuel level sensor, or sender. Advisor transmits the monitored data to the

instrument cluster and activates its mode and alert indicators, displays, and gauges. This

information may also be accessed and displayed on Advisors screens or with Cat ET.


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In addition to the four analog gauges, the tachometer, and the LCD display screen (mentioned

earlier), the instrument cluster contains up to fifteen LED indicators that show the operator the

status of a number of machine functions. When lit, they indicate the following functions:

1. Engine pre-lube activated (illuminates only if equipped with a pre-lube system)

2. winch disabled (illuminates only if the machine is equipped with a winch)

3. winch low speed lock (illuminates only if the machine is equipped with a winch)

4. winch freespool or release (illuminates only if the machine is equipped with a winch)

5. Auto KickDown activated

6. AutoShift activated

7. parking brake ON

8. Action Lamp

9. charging system fault (abnormal output at the "R" terminal)

10. Auto Blade Assist enabled (illuminates only if the machine is equipped with ABA)

11. AutoCarry active (illuminates only if the machine is equipped with AutoCarry)

12. implement lockout activated

13. FLOAT active

14. single tilt enabled

15. dual tilt enabled (illuminates only if the machine is equipped with dual tilt)


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AUTO

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ImplementLockout

Activated (12)

AutoCarryActive (11)

ChargingSystem Fault (9)

ParkingBrake On (7)

ABAEnabled (10)

ActionLamp (8)

WinchDisabled (2)

Dual TiltEnabled (15)

Single TiltEnabled (14)

FloatActive (13)

WinchLow Speed

Lock (3)

WinchFreespool orRelease (4)

AutoShiftActivated (6)

Auto KickDownActivated (5)

NotUsed

2.3 1F

132.1

EnginePre-Lube

Activated (1)

NotUsed

INSTRUMENT CLUSTER

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The heart of the CMDS is the graphical display module, which is located on the right console,

ahead of the dozer control lever. The graphical display module is referred to as Advisor.

Advisor consists of the display screen (1), the navigational buttons (2), and an internal,

self-contained ECM (not visible).

Advisor is used to access, monitor, and display operating characteristics, diagnostics and events,

and modes of operation. Advisor is also used to view and change operator preferences and

parameters, much like the Vital Information Display System (VIDS) in the previous D10R

Track-type Tractors.

Advisor also allows the serviceman to troubleshoot and adjust machine systems by:

- viewing active and logged codes and events, and clearing logged codes;

- viewing the status of machine systems and their components;

- and performing calibrations for the steering, the implement, and the power train systems.


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The Dozer Mode display area can display a number of messages which show the current dozer

mode, the current segment during the Auto Blade Assist (ABA) cycle or AutoCarry cycle, or the

status of the implement or the implement system. The Dozer Mode display area may show any

of the following messages:

- Carry (CARRY segment active - blade is in CARRY position)

- Spread (blade is moving from CARRY to a preset SPREAD position)

- Ready To Return (blade is at end of SPREAD segment - gear is Neutral)

- Return (blade has reset - not in Forward gear)

- Ready To Carry (blade is loading, next move will position for CARRY)

- Manual (Manual blade mode active - ABA or AutoCarry not armed)

- Not Reset (ECM does not know blade position)

- Resetting (blade automatically moving to find load position)

- Float (blade is in FLOAT - dozer control lever is in FLOAT position)

- Low Engine Speed (engine speed too low for ABA/AutoCarry modes)

- Wrong Gear (wrong gear for AutoCarry mode - shift the transmission to 1F)

- Service (displayed during implement calibrations)

- Implements Off (Implement Shutoff is ON, or active)

- Stowing Ripper (ripper moving to stow position - AutoStow activated)

The AutoShift Mode display area shows the current AutoShift Mode that is selected, using the

AutoShift Mode selector switch on the right operator console. Depending on how the tractor is

configured, it can display "1F-2R," "2F-2R," "2F-1R," or "Inactive," if no AutoShift Mode is

selected.

The bottom portion of the Advisor display screen is the Data Display/Menu Selection Display

Area. It displays numerous menus and sub-menus used for navigation from screen to screen. It

may also display operator warnings, system information, and system status, depending on what

menu or sub-menu selection has been made.

A "More Options" icon may also appear on the display screen. This is an indicator that moreinformation is available for selecting or displaying from the current highlighted position. This

icon may point down, up, left, or right. Using the Arrow Button that corresponds to the "More

Options" icon will allow the operator or serviceman to move to and/or view the additional

information.

At the right of the display screen is a column of five User Interface buttons. These buttons are

used to navigate through the numerous Advisor screens, to make menu selections, or to enter

data.


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The five User Interface buttons, from top to bottom, are:

1. LEFT/UP Arrow button - This button is used for screen navigation or data entry. It can be

used:

- to scroll up a vertical list or scroll left across a horizontal list;

- to decrease a setting value, such as decreasing brightness/contrast.

2. DOWN/RIGHT Arrow button - This button is also used for screen navigation or data entry.

It can be used:

- to scroll down a vertical list or scroll right across a horizontal list;

- to increase a setting value, such as increasing brightness/contrast.

3. BACK button - This button is used:

- to go up one level in a stair-step (hierarchical) menu structure, or to return to the

previous screen, much the same as the BACK Button is used in Windows Internet

Explorer;

- as a backspace, or cancel key when the operator or serviceman wishes to delete entered

characters.

4. HOME button - This button is used to return to the home menu screen, regardless of what

screen is currently displayed.

5. OK button - This button is used:

- to make selections from a screen;

- to confirm an entry, such as a password, or for saving an operator profile entry.

Navigation through the menus and sub-menus is accomplished by using the ARROW buttons to

highlight the desired selection, then pressing the OK button. The ARROW buttons are also used

to highlight a mode or to set a parameter. Pressing the OK button selects that option. (Example:

Choosing either "Enabled" or "Disabled" for the FLOAT option in the Implement Settings

menu.)

NOTE: The column of five buttons at the left of the display screen currently have no

function.


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OK

1F 1F-2RFloat

Recall Operator Settings

Display SetupOK

OKOK

Default SettingsActivated in 10 Seconds

OrPress

To RecallPrevious Settings

Start Up

Advisor will perform a self-test routine at machine start-up (key ON). After a few seconds, a

preliminary screen will appear (illustration 19). The preliminary screen displays, "Default

Settings Activated in 10 Seconds Or Press OK To Recall Previous Settings." To use the operatorprofile (settings) that were active the last time the machine was operated the operator may

acknowledge "YES" by pressing the OK button. NO is assumed by waiting 10 seconds.

If the operator answers YES by pressing the OK button, Advisor will load into its memory the

operator profile that was last used.

If the operator waits 10 seconds, the default settings (or factory settings) will be loaded into

Advisor's memory. If the operator wishes to use an operator profile (settings) other than the last

used set or the default settings, another operator profile may be selected from the "Operator"

menu selection, from the Home Menu (see the "Operator Option" section, later in this module).

After the preliminary screen has been acknowledged or has expired, "pop-up" warning screens

may be displayed if there are any active faults in any of the machine systems (see illustration 20,

next page).

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OK

1F 1F-2RFloat

Display SetupOK

Engine ECM

MID 36 ID 164-3

Injection Actuation Pressure Sensor

Voltage Above Normal Shorted High

ACKNOWLEDGE

PRESS THE OK KEY TO ACKNOWLEDGE

!

The illustration above shows a "pop-up" warning screen generated by the Engine ECM and

reported by Advisor. There may be more warning screens if there are any other active faults or

events reported to Advisor by the Engine ECM, or any other ECM on the machine. Advisor will

scroll through all of the warning screens generated by all of the active faults and events. Each of

these warning screens must be individually acknowledged by pressing the "OK" button.

Each of these warning screens contains the following information:

- The reporting ECM (in text)

- The reporting MID (module identifier, or ECM code)

- The ID (Component ID and Failure Mode Identifier)

- A text message stating the failed component

- A text message stating the failure mode of the component

- A prompt for the operator to acknowledge the warning

Acknowledging these warnings does not clear them from the reporting ECM's memory.

Acknowledging them only clears them from the screen, or "snoozes" them. They may re-occur

after a pre-determined amount of time, depending on their severity.

The CMDS provides three Warning Category Indicators (levels), utilizing "pop-up" warning

messages on Advisor's screen (see above), the front Action Light (contained in the instrument

cluster), the rear Action Lamp, and an Action Alarm.

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The three warning category indicators and the resulting combinations of the Action Lamps and

the Action Alarm are:

- Warning Category Indicator 1: A warning appears on the Advisor screen, describing

the event or diagnostic failure. The forward Action Lamp will illuminate to solid amber.The warning can be acknowledged (snoozed) by pressing the OK button, and will not re-

appear for several hours, depending on the failure or event (or if the event or failure does

not re-occur).


the event or diagnostic failure. The Action Light and Lamp will flash red, alerting the

operator to change the machine operation mode. The warning can be acknowledged

(snoozed) by pressing the OK button, and will not re-appear for one hour, depending on

the event or failure (or if the event or failure does not re-occur) and the Action Light and

Lamp will stop flashing.


the event or diagnostic failure. The Action Light and Lamp will flash red, and the Action

Alarm will pulse to alert the operator to shut down the machine. The warning can be

acknowledged (snoozed) and will continue to appear every five minutes. The Action

Light and Lamp will continue to flash red and the Action Alarm will continue to pulse

after the operator acknowledges the warning.

NOTE: If the Warning Category Indicator (fault) is related to an implement control

failure, the Advisor warning will ask if the operator desires to go to "Limp Home Mode."

If the operator chooses the YES option, Advisor will display the Limp Home Screen. The

Limp Home screen allows the operator to use Advisor to slowly and incrementally move

the implements to a position that will allow the machine to be moved for service work.

Gear selection for the transmission will be limited to first gear forward, or first gear

reverse.

NOTE: At machine start-up (key ON), the LCD display in the Instrument Cluster will

briefly display the Instrument Cluster's part number. Although the T-Model tractors all

have a common cab, the Instrument Cluster is different for the D8T, the D9T, and theD10T. This is due mainly because of differences in engine rpm between these models.

The Advisor ECM software is model-specific also, reflecting the differences in

Instrument Clusters. The Instrument Cluster and the Advisor software must match for

the Instrument Cluster to operate properly.


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OK

1F 1F-2R

Performance 1 of 2

87.8 C 1410 RPM

68.8 C76.6 C

Hydraulic Oil

Temperature

TCO

Temperature

EngineSpeed

EngineCoolant Temp

n/min

Next

Float

PERFORMANCE SCREEN 1 OF 2

OK

1F 1F-2R

506.0 kPa 40 C

26.3 Volts75 %

Fuel Level SystemVoltage

Air InletTemperature

Engine OilPressure

Performance 2 of 2

Float

Previous

PERFORMANCE SCREEN 2 OF 2

After the warning screens have been acknowledged the "Performance 1 of 2" screen will then

appear on the display (illustration 21). This is the default screen. Pressing the right ARROW

button will display the "Performance 2 of 2" screen (illustration 22).

Using the left and right ARROW buttons allows the operator to switch back and forth between

the two Performance screens. Vital information about the machine's major systems may be

easily monitored using these two screens and the in-dash Instrument Cluster.

21

22


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The two Performance screens display real-time text information for the following:

- Engine Coolant Temperature

- Engine Speed

- Hydraulic Oil Temperature

- Torque Converter Oil Temperature

- Engine Oil Pressure

- Air Inlet Temperature

- Fuel Level

- System Voltage

The Home Menu may displayed from any screen by pressing the HOME button.

INSTRUCTOR NOTE: For more detailed information about the new monitoring

system and Advisor and how to access and use all of the options, refer to SERV1790,

"Caterpillar Monitoring and Display System with Advisor for Track-type Tractors."


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23

ENGINE

The C15 ACERT technology engine is new for the D8T Track-type Tractor. The engine is

equipped with Mechanical Electronic Unit Injection (MEUI), an Air To Air

AfterCooler (ATAAC), and a new electro-hydraulic demand fan system. The C15 engine also

utilizes the A4 Engine Electronic Control Module (ECM), which is air cooled. The C15 is rated

at 231.6 net kW (310 net horsepower) at 1850 rpm. The D8T uses a "constant net" power

strategy. This means that at rated speed, and under full load, the tractor always delivers

231 kW (310 hp) at the flywheel, except during derates. When the demand fan is at maximum

speed, the Engine ECM increases gross power to 259 kW (347 hp). At minimum fan speed, theEngine ECM maintains gross power at 243 kW (326 hp). This strategy maintains a constant net

power regardless of fan requirements and provides fuel consumption benefits during low

ambient conditions.

The C15 engine is an in-line six-cylinder arrangement, with a displacement of 15.2 liters. Most

of the service points for the C15 are located on the left side of the engine.

The C15 engine meets U.S. Environmental Protection Agency (EPA) Tier III Emissions

Regulations for North America and Stage III European Emissions Regulations.


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Engine oil and filter change intervals have been increased to 500 hours, under most operating

conditions. However, engine load factor, sulfur levels in the fuel, oil quality, and altitude may

negatively affect the extended oil change intervals. Regular engine oil samplings (SOS) must

be performed every 250 hours to confirm oil cleanliness.

The C15 is functionally similar to the 3406E engine used in the D8R Series II. However, theEngine ECM and its software, the cam, the injectors, the crankshaft, the piston rods, the pistons,

and a few other components are re-engineered, reflecting the change to ACERT technology. An

electro-hydraulic demand fan is standard equipment for the D8T. The D8T may also be

equipped with an automatic/manual fan reversing feature for some applications.

The C15 ACERT technology engine specifications for the D8T Track-type Tractor are:

-Serial No. Prefix: LHX

-Performance Spec: 0K4648 (for North America), and 0K4147 (for E.U.)

-Max Altitude: 3810 m (12,500 ft.) without derate

-Gross Power: 259 kW (347 hp)

-Net Power: 231 kW (310 hp)

-Full Load rpm: 1850

-High Idle rpm (full throttle, neutral): 2200 10 (for North America), 2070 10 (for E.U.)

-Low Idle rpm: 700

NOTE: The C15 engine uses a "Ground Speed Governor" engine software strategy to

reduce the potential for engine overspeed and to maintain a constant speed in downhill

and uphill situations when there is little or no load on the blade. The Engine ECM

constantly monitors engine speed and torque converter output speed to make the

following adjustments.

- If the engine is at high idle while the machine is traveling downhill, the Engine ECM will

automatically lower engine rpm to maintain the correct torque converter output speed. In

uphill situations, the Engine ECM will automatically increase engine rpm to maintain the

correct torque converter output speed, up to a maximum of 2200 rpm.

- If the engine is in an overspeed condition (2600+ engine rpms), the Power Train ECM will

automatically apply the brakes (up to 8% of brake capacity) in an effort to slow the

machine. If this auto-braking strategy does not lower engine rpms to an acceptable level,

Advisor will warn the operator to change the operating mode (downshift or manually

apply the brakes).

- If the operator has set an intermediate engine speed using the decelerator and the high-

low idle switch, this strategy is ignored in uphill situations.

On machines built for the E.U., the torque converter output speed target is

approximately 5% lower than those built for North America, due to more stringent noise

requirements. Accordingly, the ground speed target is a bit slower, also. This will result

in slightly slower speeds when "roading" the machine and when backing up.


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24

Major service points accessible from the left side of the engine are:

1. coolant sampling port (SOS)

2. engine oil fill tube

3. engine oil filter and associated service points (discussed later in this presentation)

4. air filter access cover

5. engine oil dipstick

6. primary fuel filter and water separator and electric fuel priming pump

7. secondary fuel filter and associated sensors (discussed later in this presentation)

8. A4 Engine ECM

9. starter

10. prelube motor and pump (if equipped)

11. high-speed oil change connectors for engine oil and power train oil


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23 5 6

7

8

910

4

11

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25

Major service points accessible from the right side of the engine are:

1. turbocharger

2. air conditioning compressor

3. thermostat (temperature regulator) housing

4. alternator

5. coolant flow switch

6. external engine oil cooler

7. power train oil cooler

8. block heater element


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4

5

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1

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26

Located on the left side and toward the rear of the engine is the 10-micron primary fuel filter (1).The primary fuel filter contains a water separator which removes water from the fuel. Water in a

high pressure fuel system can cause premature failure of the fuel injectors due to lack of

lubricity and corrosion.

Fuel is drawn from the primary fuel filter by the fuel pump (shown later) and is then returned to

the 2-micron secondary fuel filter (2). The secondary fuel filter removes all contaminants that

could damage the fuel injectors. Fuel filters should be replaced regularly, according to the

guidelines on the D8T Operation and Maintenance Manual (SEBU7763) to ensure that clean

fuel is always delivered to the fuel injectors.

The electric fuel priming pump (4) is integrated into the primary fuel filter base. It is activated

by pushing the electric fuel priming pump switch (5). Also shown is the fuel system air purge

valve (3), which is used to purge the priming pump of any air that might be introduced after

changing the fuel filters. The fuel priming pump is used to fill the fuel filter housings after the

filter elements have been replaced. The fuel priming pump is capable of forcing the air from the

entire fuel system.

After the fuel filters have been replaced, activate the priming pump and then open the air purge

valve. (Always place a suitable container under the purge valve outlet to catch any fuel that

escapes through the valve.)


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456

7

3

8 9

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Trapped air and a small amount of fuel will escape through the purge valve as the pump primes

itself. When the purge valve emits only fuel, the purge valve should then be closed. Continue

operating the priming pump until it is determined that all air has been forced from the entire fuel

system - from the priming pump to the fuel tank. It should be noted that the priming pump

produces enough pressure to force fuel past the bypass valve in the fuel transfer pump and pastthe fuel pressure regulator (check valve). Also note that the main disconnect switch must be

turned to the ON position and the key start switch must be in the OFF position for the fuel

priming pump to run.

Also visible in the illustration above is the block heater receptacle (6). 120V and 240V versions

of the block heater are available.

Also shown is the auxiliary start receptacle (7), which may be used to supplement the batteries

when the temperatures are extremely cold or the batteries are low.

The ether aid solenoid (8) is also shown in illustration 26 (the ether canister is not installed).When the ether aid solenoid is energized, ether is injected into the intake manifold inlet tube (9).

The Engine ECM controls ether injection when the conditions warrant its use. The Engine ECM

monitors the intake air temperature sensor and the coolant temperature sensor to determine when

to inject ether. If the temperature of the engine coolant or the intake air is less than 0C (32F),

AND the engine speed is greater than 35 rpm, but less than low idle speed (700 rpm), then ether

injection will be activated. Once the engine starts and the low idle speed is attained, the Engine

ECM then looks to the ether injection map (contained in the engine software) to determine how

long to provide ether injection.

The status of the ether aid solenoid may be viewed through the Advisor Panel (Engine SystemStatus screens) or by using Cat ET.


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27

Installed in the top of the secondary fuel filter base are the following fuel system components:

1. fuel temperature sender

2. fuel pressure regulator (check valve)

3. fuel pressure sensor

4. secondary fuel filter bypass switch (differential pressure switch)

The status of the fuel temperature, the fuel pressure, and the state of the secondary fuel filter

bypass switch may be viewed through the Advisor panel (Engine System Status screens) or

through Cat ET.


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2

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28

The fuel transfer pump (1) is located at the front left of the engine, near the bottom of the

engine. The fuel transfer pump is driven by the front gear train. Fuel is drawn from the primary

fuel filter and water separator through the upper fuel line (2) by the fuel transfer pump and is

returned to the secondary fuel filter through the lower fuel line (3).

The primary (crankshaft) engine speed/timing sensor (4) is located just below the fuel transfer

pump. The crankshaft speed/timing sensor provides crankshaft speed and position information

to the Engine ECM. This information is also shared with the Power Train ECM as engine speed

information. The C15 engine has no engine output speed sensor at the flywheel housing. This

is a change from the D8R Series II, which had an engine output speed sensor installed in theflywheel housing which provided engine speed information to the Power Train ECM.

The timing calibration probe adapter (7X1171) is threaded into the timing calibration port (5),

after removing the plug. The timing calibration probe, or transducer (6V2197), is then inserted

into the adapter. Maintain a 1 mm (.040") air gap between the end of the probe and the

machined surface of the crankshaft counterweight when positioning the probe. The probe will

sense a notch that is machined in the crank counter-weight. Cable 7X1695 is used to connect

the probe to the timing calibration connector (illustration 31).


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4

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29

The engine pre-lube pump (1) is driven by an electric motor (2). (The pre-lube pump is no

longer driven by the starter motor.) If the machine is equipped with pre-lube, the pre-lube pump

and motor are installed on the left side of the engine, just above the oil pan. Engine pre-lube is

used to ensure that there is sufficient oil pressure throughout the engine oil system before

allowing the starter to engage and start the engine. This strategy prevents premature wear of

critical engine components. When the key start switch is moved to the START position, the

prelube pump may run for a short time before the starter engages.

The Engine ECM determines when to activate the pre-lube pump by monitoring the engine oil

pressure sensor. If the oil pressure is less than 30 kPa (4.4 psi) the Engine ECM will activate the

pre-lube pump until the oil pressure reaches 30 kPa (4.4 psi), or for up to 45 seconds, whicheveroccurs first. To override this strategy, turn the key switch to the START position. Then cycle

the key start switch to the OFF position and then back to the START position again within one

second. This action will allow the starter to engage without cycling the pre-lube pump.

The ecology drain (3) for engine oil is located on the left side of the oil pan. The steel tube (4)

to the rear of the pre-lube pump connects to the Quick-Evac connector for engine oil.

NOTE: When the pre-lube cycle is activated, Advisor will inform the operator that pre-

lube is activated and to keep the key start switch in the "START" position until the engine

is running.


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3

4

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30

The atmospheric pressure sensor (1) and the engine oil pressure sensor (2) are installed in a

block that is located on the lower left side of the engine, between the pre-lube pump and the

starter.

The status of these two pressure sensors may be viewed through the Advisor panel (Engine

System Status screens) or through Cat ET. Engine oil pressure may also be viewed on the

Performance Screen 2 of the Advisor display.


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31

The starter (1) is located on the left side of the engine, and is mounted to the front side of the

flywheel housing.

Just above the starter is the air cooled A4 Engine ECM (2). The timing probe connector (3) is

fastened to the wiring harness coming from the J2/P2 connector (4). The J1/P1 connector (5) is

a 70-pin connector and the J2/P2 connector is a 120-pin connector.

The hydraulic hose and fitting (6) supplies lube oil to the flywheel housing. The other end of

the hose is connected to a fitting on the side of the torque converter oil inlet port, at the left rear

of the torque converter housing. A small amount of power train oil flows through the hose toprovide lubrication for the flywheel and pump drive gears. The power train scavenge pump

returns the oil from the bottom of the flywheel housing to the power train main sump.


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3

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6

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32

Also accessible from the left side of the engine, and located just above the starter, is the cover

for inserting the engine turning tool (1). Removing this cover allows the serviceman to insert

the 9S9082 engine turning tool to manually turn the engine.

To find Top Dead Center (TDC) of cylinder number one, remove the plug in the TDC port (2),

then insert the longer bolt from the cover (1) into the port (2). While applying light pressure to

the bolt, turn the engine in the direction of engine rotation until the bolt drops into the hole

machined in the front face of the flywheel. A spring-loaded timing pin (136-4632) may also be

used to find TDC, instead of the long bolt from the cover.


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The intake air temperature sensor (1) is located on the left side of the engine, just below the

primary fuel filter and water separator. The status of this pressure sensor may also be viewed

through the Advisor panel (Engine System Status or Performance screen) or through Cat ET.

The "Crank-Without-Inject" connector (2) is fastened to the wiring harness just below and in

front of the intake manifold. Removing the plug (3) from the "Crank-Without-Inject"

connector (2) and inserting the plug (4) at the left will electronically disable the fuel injectors.

This allows the engine to be turned (cranked) using the starter, but without the engine starting.

No fuel will be injected into the cylinders in this mode so that the engine cannot start and run.

The status of the "Crank-Without-Inject" feature may be viewed through the Advisor panel

(Engine System Status screens) or through Cat ET.

33

34


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1

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35

Located at the left front of the engine, are the following service points:

1. engine oil filter

2. engine oil filler tube

3. engine oil sampling port (SOS port)

4. engine oil pressure port

5. engine oil dipstick

NOTE: The engine oil pressure port tests the engine oil pressure after the oil is filtered.

The engine oil sampling port is positioned upstream of the oil filter so an oil sample

reflects the cleanliness of the oil before the filter.


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The intake manifold air (boost) pressure sensor (1) is located at the upper left, and at the front of

the engine, just ahead of the engine oil filter.

Also located here, and installed in the rear of the timing gear cover, is the secondary (camshaft)

engine speed/timing sensor (2).

The status of the intake manifold pressure sensor may be viewed through the Advisor panel


36

37


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The coolant temperature sensor (1) is installed at the right front corner of the engine, in front of

the water pump (2). The status of the coolant temperature sensor may be viewed through the

Advisor panel (Engine System Status screens or Performance screen) or through Cat ET.

The water pump (2) is located behind and below the alternator, at the right front of the engine.

Just above the water pump is the thermostat (coolant temperature regulator) housing (3). Two

thermostats are contained in the housing. The shutoff valve for the cab heater return line (4) and

the shutoff valve for the cab heater supply line (5) are located to the rear of the thermostat

housing. The coolant flow switch (6) is situated outboard from the thermostat housing and

installed in the cast tube exiting the water pump.

The status of the coolant flow switch may be viewed through the Advisor panel (Engine System

Status screens) or through Cat ET.

38

39


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3

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Also accessible at the right front of the engine is the alternator (1) and the air-conditioning

compressor (2). Just to the rear of the air-conditioning compressor is the turbocharger (3).

The turbocharger on the C15 ACERT technology engine uses a standard wastegate (4), which is

operated by a vacuum line (5). The wastegate acts as a bypass valve for exhaust gasses. When

the wastegate opens it allows some of the exhaust gasses to bypass the turbocharger. The

wastegate limits boost pressure, which in turn, limits the maximum engine cylinder pressure.

The center section of the turbocharger is water cooled (line not visible) and is lubricated with

engine oil, which is supplied through the hard steel tube (6).

40

41


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5

6

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42

The oil-to-water type engine oil cooler (1) is located along the lower right side of the engine.

Oil from the oil filter enters the cooler at the oil inlet (2) and passes through tubes surrounded by

engine coolant. The cooled oil then exits the cooler at the oil outlet (4) and enters the engine

block at port (5).

When the engine is started and the oil is cold, some of the oil bypasses the engine oil cooler

through the cooler bypass tube (3).

Coolant enters the engine oil cooler at the front (right, above) of the cooler and exits at the rear,

where it then enters the power train oil cooler (6). After flowing around the oil filled tubes inthe power train oil cooler, the coolant enters the right side of the engine block through a port

(not visible) behind the power train oil cooler.

NOTE: When troubleshooting the cooling system it must be understood that both the

engine oil cooler and the power train oil cooler are heat sources that raise the

temperature of the coolant before it enters the engine block.


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The turbo inlet pressure sensor (1) is installed at the outlet of the air filter canister and is

accessible from the right side of the engine.

The turbo inlet air pressure sensor is used to determine air filter restriction. The Engine ECM

compares the turbo inlet air pressure to the atmospheric air pressure and calculates a pressuredifferential between the two pressures. If the pressure differential is too great, it can indicate

that the air filter is clogged and needs to be replaced.

Also visible in this illustration is the dust ejector tube (2) that connects the intake air precleaner

to the muffler.

The status of the turbo inlet air pressure sensor may be viewed through the Advisor panel


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44

Fuel System

Fuel is drawn from the fuel tank through the primary fuel filter (10-micron) and water separator

by a gear-type fuel transfer pump. The fuel transfer pump then directs the fuel through the

secondary fuel filter (2-micron).

From the secondary fuel filter,the fuel is then directed to the cylinder head and into the fuel

gallery, where it is made available to each of the six MEUI fuel injectors. Any excess fuel not

injected leaves the cylinder head. From the cylinder head, the fuel is directed back to the fuel

tank through the fuel pressure regulator, which maintains fuel pressure of 558 50 kPa

(81 7 psi). The fuel pressure regulator is a check valve that is installed in the secondary fuelfilter base.

From the fuel pressure regulator, the excess fuel flow returns to the fuel tank. The ratio of fuel

between combustion and fuel returned to tank is approximately 3:1 (i.e. four times the volume

required for combustion is supplied to the system for combustion and injector cooling purposes).

A differential pressure switch is installed in the secondary fuel filter base and will alert the

operator, via Advisor, of a clogged fuel filter. This Advisor warning indicates that the secondary

fuel filter is being bypassed and that the fuel filter should be replaced immediately. The

recommended fuel filter change frequency interval is 500 hours, under optimum conditions.


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Fuel Tank

Fuel TransferPump Primary

Fuel FilterSecondaryFuel Filter

Electric FuelPriming Pump

Fuel PressureRegulatorFuel Gallery

C15 ACERT ENGINE FUEL DELIVERY SYSTEMD8T TRACK-TYPE TRACTOR

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Cooling System

Shown above is a schematic of the cooling system for the D8T Track-type Tractor with the C15

ACERT technology engine. The C15 uses an Air To Air AfterCooler (ATAAC) to cool the

intake air. The ATAAC is mounted vertically in the radiator guard (not pictured, in the above

illustration). It is in line with, and to the left of the AMOCS radiator cores. The hydraulic oil

cooler is an oil-to-air type cooler and is mounted vertically, behind the AMOCS cores.

The AMOCS radiator contains six cores and are the standard "two-pass" design. The hydraulic

demand fan is controlled by the Engine ECM. The fan mounted on the front of the radiator

guard and is situated in front of the radiator. This arrangement draws air in through the sides ofthe engine compartment, then through the hydraulic oil cooler, the radiator and the ATAAC, then

exits the front of the tractor. This design minimizes the possibility of the fan ejecting debris into

the radiator or ATAAC cores (when the fan reversing feature is not activated).

Coolant flows from the water pump, through the engine oil cooler, then through the power train

oil cooler, and then into the engine block. Coolant then flows through the engine block and into

the cylinder head.


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From the cylinder head, the coolant flows to the temperature regulators (thermostats) and either

goes directly to the water pump through the bypass tubes or to the radiator, depending on the

temperature of the coolant. When the engine is cold, the coolant flows directly to the water

pump through the bypass tube. As the temperature of the coolant increases, the thermostats

open and the coolant then flows to the radiator. The thermostat housing for the C15 enginecontains dual thermostats. The opening temperature for these thermostats is 81 - 84C (178 -

183F). The thermostats should be fully open at 92C (198F).

Hot coolant enters the bottom of the radiator and it is cooled the first time as it flows upward

through the front side of the AMOCS cores. The coolant is cooled a second time as it flows

down the back side of the cores. The coolant then exits the radiator and returns to the water

pump.

A small amount of coolant flows to the turbocharger from the thermostat housing, for cooling

purposes, and is then directed to the shunt tank. Coolant from the shunt tank is directed to the

water pump.

The fill tube and the radiator cap for the cooling system are located on top of the shunt tank.

The shunt tank is located directly above the radiator core in the engine compartment. Access to

the fill tube is provided by lifting a spring hinged door on top of the radiator guard.

A sight glass in the shunt tank is visible from the left side of the engine compartment. The sight

glass should always be filled with coolant. If any air is seen in the sight glass, coolant needs to

be added to the system through the cap on the shunt tank.

The air vent lines remove air from the cooling system while the system is being filled and during

operation. The shunt tank is a reservoir and retains the expansion volume of the coolant as thecoolant temperature increases. The level of the coolant in the shunt tank will rise as the coolant

increases in temperature. The coolant level in the shunt tank will fall as the temperature of the

coolant decreases.

A drain valve (illustration 48) is present below the radiator and is used to drain coolant from the

radiator cores, the engine oil and power train oil coolers, and the cab heater circuit.


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Mounted vertically on the back side of the D8T radiator guard is the hydraulic oil cooler (1). In

front of the hydraulic oil cooler are the six AMOCS radiator cores (2). At the top of the radiator

guard is the shunt tank (3). Mounted vertically on the left side of the radiator guard is the air

conditioning condenser (4). In front of the condenser, and to the left of the AMOCS cores is the

ATAAC core (5).

Hot coolant enters the radiator at the inlet tube (6). It flows up through the front side of the

AMOCS cores, then down the back side, passing twice through the cores. The coolant then

exits the radiator through the outlet tube (7) and returns to the water pump.

The radiator drain line from the oil coolers (8) and the drain valve (9) can also be seen here.

47

48


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49

Opening the grill on the front of the radiator guard gains access to the fan (1) (behind the brush

guard) and the hydraulic demand fan motor (2) with a self-contained anti-cavitation valve.

If the machine is equipped with a reversing fan, a bi-directional fan motor replaces the standard

fan motor with anti-cavitation valve. The fan reversing valve (3) is located at the lower left of

the radiator guard.

INSTRUCTOR NOTE: The hydraulic demand fan and the reversing fan strategy will

be discussed later in this presentation.


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50

Hydraulic Demand Fan System

Standard on the D8T Track-type Tractor is the hydraulic demand fan. Although the fan is part

of the hydraulic system, it is controlled by the Engine ECM. The Engine ECM considers four

inputs for controlling the fan. The hydraulic oil temperature sensor, the engine intake air

temperature sensor, and the engine coolant temperature sensor all provide temperature

information to the Engine ECM. The Engine ECM monitors all three of these temperature

inputs. The highest temperature (relative to the percentage of its temperature map) is the

controlling temperature for fan speed. The fan pump discharge pressure sensor is the fourth

input to the Engine ECM. Fan pump discharge pressure is controlled by the Engine ECM todetermine fan speed.

The Engine ECM monitors the temperature inputs and also considers fan pump discharge

pressure to provide a signal to the (proportional) fan pump pressure control solenoid. When the

solenoid receives minimum current from the Engine ECM, maximum flow is sent to the fan

motor, causing the fan to turn at the maximum controlled rpm (about 1350 + 25 rpm), as shown

above. Maximum mechanical pump pressure (high pressure cutoff - no current or a failed

solenoid) is set to approximately 15000 + 860 kPa (2175 + 125 psi). Maximum pressure

regulated by the Engine ECM software is approximately 13250 + 500 kPa (1922 + 75 psi).


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Cat ET may be used to reset the maximum controlled fan system pressure from the maximum

pressure set at the factory. This adjustment may be necessary to correct the maximum

controlled fan speed due to differences in altitude between the factory and the tractor's work site.

In cooler weather, the Engine ECM may utilize an engine software strategy called "Cool Engine

Elevated Idle Strategy" when the following conditions are met:

- Coolant Temperature < 70C (158F)

- Parking brake is set to ON

- Transmission in NEUTRAL

- Throttle switch set to LOW IDLE

Under these conditions, the Engine ECM will automatically increase engine speed, up to

1100 rpm, in an effort to increase coolant temperature. When any of the four conditions are not

met, the strategy is ignored.

NOTE: The D8T does not utilize a fan bypass valve for cold weather.


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51

The standard hydraulic demand fan schematic with the fan at minimum speed is shown above.

If maximum fan speed is not required, the fan pump pressure control solenoid is energized,

causing the fan to turn at a slower speed. Minimum fan speed is attained when the fan pump

pressure control solenoid is completely energized (approximately 450 + 50 rpm). Fan pump

pressure at minimum speed should be set to approximately 1827 240 kPa (265 35 psi).

If communication is lost between the Engine ECM and the fan pump pressure control solenoid,

the fan will default to the maximum mechanical pressure setting, which is approximately

15000 + 860 kPa (2175 + 125 psi). This results in a fan speed of approximately1369 rpm (as setat the factory).

NOTE: If the engine is in the overspeed condition, the Engine ECM will regulate the

fan toward minimum pressure in an effort to protect the fan hydraulic system.


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52

As stated earlier, the Engine ECM constantly monitors the intake air temperature, the engine

coolant temperature, and the hydraulic oil temperature. When temperatures require maximum

controlled fan speed, the Engine ECM de-energizes the fan pump pressure control solenoid,

sending the least amount of signal, as shown above. (When communication is lost to the pump

control solenoid and no current is sent to the solenoid, the mechanical high pressure cutoff will

raise the fan speed to its absolute maximum speed.)

With the solenoid de-energized, the pressure control spool spring forces the top half of the

pressure control spool up. This blocks pump output oil in the pump control spool spring

chamber from draining to tank through the case drain passage, which causes the pump controlspool spring chamber to become pressurized. The force of the spring at the top of the pump

control spool, plus the pressure of the oil, is then greater than the oil pressure at the bottom of

the pump control spool. The pump control spool is held down, blocking pump output oil from

entering the signal passage to the actuator piston in the pump. The actuator piston is then open

to drain.

With only tank pressure in the actuator piston, the bias spring moves the pump swashplate to an

increased angle, causing the pump to UPSTROKE, providing controlled maximum flow to the

fan motor. This condition results in maximum controlled fan speed.


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53

When a slower fan speed is required, the Engine ECM energizes the fan pump pressure control

solenoid (proportional to temperature data) as shown above.

With the solenoid energized, the solenoid pin pushes down on the top half of the pressure

control spool, against the force of the pressure control spool spring. This allows oil in the pump

control spool spring chamber to drain to tank through the case drain passage, lowering the

pressure in the spring chamber. The force of the spring at the top of the pump control spool plus

the pressure of the oil is now less than the oil pressure at the bottom of the pump control spool,

due to the orifice effect of the passage through the pump control spool. The pump control spool

then moves up, allowing pump output oil to enter the signal passage. This flow of oil to thepump actuator piston causes pressure in the pump's actuator piston to increase.

The increased pressure in the actuator piston overcomes the force of the pump bias spring. This

causes the swashplate to move to a decreased angle, and the pump DESTROKES. The pump

then provides less flow to the fan motor, resulting in a slower fan speed.

The illustration above shows the fan pump at minimum angle, or minimum flow. This will

cause the fan motor to turn at its slowest speed.

Refer to RENR7527, "Systems Operation/Testing and Adjusting for the D8T Track-type Tractor

Hydraulic System" for information regarding adjustment of the hydraulic demand fan.


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54

If the machine is equipped with a reversing fan, a fan reversing valve will be installed at the

lower left front of the radiator guard and a bi-directional fan motor will replace the standard fan

motor.

For machines equipped with the optional reversing valve, the Engine ECM will automatically

activate the fan reversing valve solenoid at pre-determined intervals (engaged in reverse gear

only). Fan reversing intervals and duration are programmable using Cat ET. The fan may also be

reversed manually using the manual reversing fan switch, which is located ahead of the dozer

control lever, and just below the Advisor display screen.

The illustration above shows the fan hydraulic system with the reversing function activated.Activating the manual reversing fan switch energizes the reversing solenoid valve. This action

directs some of the oil to shift the two pilot operated reversing valves, which in turn reverses the

flow of oil to and from the fan motor. The fan will then reverse directions, causing air to flow in

the opposite direction through all the cooler cores (radiator, ATAAC, and hydraulic oil cooler).

When the engine software determines it is time for the fan to reverse directions, it will energize

the reversing valve solenoid only when the transmission is shifted to reverse. This strategy helps

minimize the chances that any material spilling over the top of the dozer blade (when pushing

material) will be ejected into the fan blades and secondarily, into the radiator cores. This strategy

helps minimize the potential for damage to the fan blades and the radiator fins.


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The hydraulic demand fan pump (1), is mounted to the rear of the steering pump, at the upper left

of of the flywheel housing. Shown is the pressure tap for Hydraulic Fan Pump Discharge pressure

(HFPD) (2), the fan pump pressure sensor (3), the fan pump pressure control solenoid (4), the

pump control spool adjustment screw (5), and the pump pressure control spool (6).

The hydraulic demand fan motor is mounted to a bracket at the front of the radiator guard.

Visible in illustration 56 is the fan motor (7), the fan motor case drain line (8), and the fan motor

inlet and outlet ports (9). The fan reversing valve (10) is only present on machines equipped with

the reversing fan attachment.

The status of the fan pump pressure sensor may be viewed through the Advisor panel (Engine

System Status screens) or through Cat ET.

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For machines equipped with a reversing fan, the fan reversing valve (1) is mounted in the lower

left corner of the radiator guard, just behind the grill doors.

Service points on the fan reversing valve shown here are:

2. fan reversing valve solenoid (energized to reverse the flow of oil to the fan motor)

3. two crossover relief valves (used for fan motor anti-cavitation purposes)

4. two pilot operated reversing valves

5. main relief valve for the reversing fan circuit

The status of the fan reversing valve solenoid may be viewed through the Advisor panel (Engine

System Status screens) or through Cat ET.

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58

POWER TRAIN

Shown above is an illustration which identifies the relative location of all of the major power

train components for the D8T Track-type Tractor.

During this presentation, various colors are used to denote pressures within the systems. A

legend outlining the meanings of this color code can be found in the back of this module.

Numerous upgrades have been implemented in the power train for the D8T Track-type Tractor,

as compared to the D8R Series II machine. The most prominent of these upgrades include:

- the elimination of the transmission intermediate speed sensors

- new transmission output speed sensors that are more reliable and easy to install;

- elimination of transmission clutch engagement pressures, using the common top pressure

strategy for the power train;

- remote pressure test ports for all power train pressures;

- relocation of the priority valve, for easier access; and

- a new A4 Power Train ECM, which controls the transmission, the braking, and the

steering.


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Power TrainOil Cooler

Power TrainOil Pump

TransmissionCharging Filter

Bevel andTransfer Gears

SteeringDifferential

TransmissionHydraulic Control

Torque ConverterCharging Filter

PT Oil Fill Tubeand Dipstick

ElectronicBrake Valve

Torque ConverterOutlet Relief Valve

Priority Valve

Engine

Transmission

Final Drives

Lube DistributionManifold

andTorque ConverterInlet Relief Valve

Torque Divider

Power Train ECM

Service Brakes

Remote Pressure Taps(TC In, TC Out, FW Lube)

TransmissionPressure Test Ports

Brake PressureTest Ports

D8T POWER TRAINCOMPONENT IDENTIFICATION

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Power Train Electronic Control System

The illustration above is a simplified schematic that shows all of the major hydraulic

components and the major electronic components in the power train system.

The The Power Train Electronic Control System consists of all the inputs to and outputs from

the Power Train ECM, including the Power Train ECM. The Power Train ECM and its

so

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