NINE SPEED TRANSMISSION Aluminum Case Triple Countershaft Reliable and Durable On/Off Highway Applications Versatile Power Take-Off Capabilities

GearingAll the T300 gearing uses a spur type design for maximum efficiencyand minimum friction.Gear blanks are designed with the aid of com-puters to optimize the balance between weight and strength.Teeth arecut to a precise geometry to insure quiet, uniform rotating motion andthen carburized to assure the intended loads can be carried withoutbreaking or wearing. In top gears, dovetail clutch teeth maintainengagement under varying loads.Top gear in all T300 transmissions is an overdrive.The overdrive allowsrequired highway speeds to be met at the recommended enginespeed with lower driveline torques Because driveline torques are lower,lighter, less expensive shafts and slower, more durable rear axles carri-ers can be speced.

LubricationSplash lubrication is standard for the T300.Gears and bearingsreceive lubrication from the lower countershaft dipping and spinning inoil. For extreme operating conditions or unusually high loads, a pumpcan be speced to assure lubricant flow to critical areas.Magnetic drainplugs are also standard as is a main case magnetic chip trap toremove metallic contaminants from circulation.

CaseThe T300 case is a permanent mold, high strength, aluminum alloycasting .An SAE #1 bell housing is cast integral with the case to forma one-piece, light weight component with maximum rigidity and nomisalignment.Within the case, iron bearing retainers support counter-shaft and mainshaft bearings to provide rigidity and fit integrity through-out the life of the transmission.

Because of the excellent heat transfer properties of aluminum, T300snaturally run cool and have less requirement for auxiliary transmissionoil coolers.For those applications which do require additional cooling,oil-to-air and oil-to-water systems are available.

CountershaftsThe hallmark of the T300 is its triple countershaft design.Spreadingthe load over three shafts rather than just two lowers the stress oncomponents and increases life.The layout of the three shafts gives theT300 a compact design and results in shorter transmission whichimproves driveline angularity.The countershafts are forged alloy steel with both integral andpressed-on gears.Tapered roller bearings, which have the highestload carrying capacity in the smallest envelope, insure a smooth, longoperating life.

Improved Shift QualityAll of the T300 transmissions are based on an Hshift pattern and fea-ture improvements to make the operation easier and more comfort-able.The shift rail profile and springs have been redesigned to smoothtransitions in and out of neutral with each up and down shift.Additionally, fine pitch sliding clutches permit quicker, smoother shiftsas well as improved durability.Shift levers have also been revised for atighter, more ergonomic shift pattern and isolated to reduce vibration.Range shifts are executed after toggling a selector on the front of theshift knob.

Power Take-Off CapabilitiesAs the leader in vocational applications, all the T300 transmissionsoffer as standard main case, speed dependent SAE 6 and 8 bolt PTOmounts on the right and left sides, respectively.Rear mounts on any ofthe three countershafts are also available.

The T309LR is a general purpose transmission for on/off high-way applications. Like the T309, 40% steps make it easy to shiftand compatible with any of the Mack engines. Top gear remains.71:1 overdrive while a lower first gear of 13.93:1 gives it better

Mack Trucks, Inc., Allentown, Pennsylvaniawww.macktrucks.com

FEATURES

T-309LR

slow speed control and a wider range of 19.56:1. Additionally,the T309LR offers a slow 24.58:1 reverse ratio for maximumcontrol while backing.

A SALES ENGINEERING PUBLICATION 2002 Mack Trucks, Inc.

The information in this brochure was accurate as of the day of publication. MackTrucks, Inc. reserves the right to make changes in specifications, equipment ordesign, or to discontinue models or options without notice at any time.

Printed in U.S.A.

TYPE 9 SPEED OVERDRIVE, TRIPLE COUNTERSHAFT LENGTH* 31.40" [798 mm] WEIGHT (DRY) 665 LB [302 kg] OIL CAPACITY 24 PINTS [11.36 I] TORQUE RATING 1800 LB. FT. [2 440 Nm] NUMBER OF SPEEDS

FORWARD NINEREVERSE TWOOVERALL TRANSMISSION RANGE 16.01:1

CASE, BELL HOUSINGMATERIAL ONE-PIECE HEAT-TREATED ALUMINUMBELL HOUSING TYPE SAE#1

TYPE OF GEARS SPUR CONTROL SHIFT LEVER WITH AIR SHIFT RANGE SELECTOR LUBRICATION SPLASH DRAIN PLUG MAGNETIC POWER TAKE-OFF OPENINGS

LEFT SIDE-STANDARD SAE 8 BOLT 70% OF ENGINE RPMRIGHT SIDE-STANDARD SAE 6 BOLT 70% OF ENGINE RPMREAR PTO DRIVE 70% OF ENGINE RPM

800

1200

1400

1600

0 10 20 30 40 50 60 70

ENGI

NE S

PEED

(RPM

)

Transmission Shift Chart

1000

600 80VEHICLE SPEED (MPH)

1800

* From Bell Housing mounting flange to forward seating surface of companion flange or yoke.

TRA058A 136 1310 2/2002 (2/20/02)

NEUTRAL

Lo

51

73

62

84

R

Gear Ratios

Shift Pattern and Shift Lever

T-309LR

RANGEUP-HI

DOWN -LO

T-309LR w/1800 RPM ENGINE, REAR RATIO 4.42 AND 11R22.5 TIRES (BASED ON 504 TIRE REVS PER MILE)

%GEAR RATIO STEP

1st 13.932nd 7.45 873rd 5.33 404th 3.83 395th 2.73 406th 1.94 417th 1.39 408th 1.00 399th 0.71 41

REV Lo 24.58REV Hi 6.41