16 GEARS April 2007 VW and Audi recently introduced the direct shift 6- speed automatic transmission: a unique design that puts a new spin on an old standard gearbox. This new transmis- sion combines the design of a sliding- gear manual transmission with the con- trols of an automatic. The transmission model is identified as the 02E, and it’s already showing up in some VW Beetle and Audi TT models. At first glance, the 02E looks like a cross between a Honda automatic and a KM162. It uses a standard gearbox con- figuration to control three individual gear ranges, but with two separate input shafts to split the three gear ranges into six.(Figure 1). Externally the unit looks like a typical A/T, but without a torque con- verter or planetary gearsets. The gear selector operates a cable whose only purpose is to lock and unlock the park gear; all other gear selections are com- puter controlled. Some models have Tiptronic controls on the steering wheel to provide the driver with a means of forcing the shifts manually. The 02E is also available in a 4WD version. Internally, the transmission is laid out like a 3-speed manual transmis- sion. To provide six forward speeds and one reverse, it has two main inputs shafts and two secondary shafts. Each input shaft is driven by its own large, multi-friction hydraulic clutch assem- bly, located behind the flywheel. To keep things straight, the outer input shaft with clutch and gears is called the 1st Input. The inner input shaft, clutch and attached gears is called the 2nd Input. Either secondary shaft can drive the output transfer shaft to apply torque to the final drive member. There’s a separate shaft with slider and gear to operate reverse. (Figure 2). Each multi-friction clutch assem- bly is a sealed unit, controlled by the computer. This design allows each input shaft to operate independently. Depending on which gear you select, the clutch is applied hydraulically to enable you to pull away from a stop, and to engage the next gear range needed. (Figure 3). Mechanically the gear changes operate by applying engine torque through one input shaft to a slider- coupled gear on one of the secondary shafts. To make a gear change, the com- puter preselects a gear on the mainshaft that connects to the disengaged clutch. Hydraulic actuators or servos move the sliders in the direction necessary to lock the gear to the shaft. Next, the clutch that’s currently engaged starts to release. At the appro- priate time, the computer begins to apply the other clutch assembly. The computer makes all mechanical operations and decisions to select gears and control the clutches — more on that later. By having selected a gear and then alternately engaging the multi-friction clutch, the transmission applies torque smoothly to the wheels in the selected ratio. The included figures show the two clutch assemblies. The outer clutch is called Main Clutch No. 1. This clutch drives the front two gears on the main 1st input shaft. These gears provide the power flow for 1st, 3rd, 5th and Reverse. (Figure 4). Figure 1: Cutaway View of 02E Transaxle by Dave Skora
Transcript
16 GEARS April 2007
VWand Audi recently introduced the direct shift 6-
speed automatic transmission: a unique design that puts a new spin on an old standard gearbox. This new transmis-sion combines the design of a sliding-gear manual transmission with the con-trols of an automatic. The transmission model is identified as the 02E, and it’s already showing up in some VW Beetle and Audi TT models.
At first glance, the 02E looks like a cross between a Honda automatic and a KM162. It uses a standard gearbox con-figuration to control three individual gear ranges, but with two separate input shafts to split the three gear ranges into six.(Figure 1).
Externally the unit looks like a typical A/T, but without a torque con-verter or planetary gearsets. The gear selector operates a cable whose only purpose is to lock and unlock the park gear; all other gear selections are com-puter controlled. Some models have Tiptronic controls on the steering wheel to provide the driver with a means of forcing the shifts manually. The 02E is also available in a 4WD version.
Internally, the transmission is laid out like a 3-speed manual transmis-sion. To provide six forward speeds and one reverse, it has two main inputs shafts and two secondary shafts. Each input shaft is driven by its own large, multi-friction hydraulic clutch assem-bly, located behind the flywheel. To keep things straight, the outer input
shaft with clutch and gears is called the 1st Input. The inner input shaft, clutch and attached gears is called the 2nd Input. Either secondary shaft can drive the output transfer shaft to apply torque to the final drive member. There’s a separate shaft with slider and gear to operate reverse. (Figure 2).
Each multi-friction clutch assem-bly is a sealed unit, controlled by the computer. This design allows each input shaft to operate independently. Depending on which gear you select, the clutch is applied hydraulically to enable you to pull away from a stop, and to engage the next gear range needed. (Figure 3).
Mechanically the gear changes operate by applying engine torque through one input shaft to a slider-coupled gear on one of the secondary shafts. To make a gear change, the com-puter preselects a gear on the mainshaft
that connects to the disengaged clutch. Hydraulic actuators or servos move the sliders in the direction necessary to lock the gear to the shaft.
Next, the clutch that’s currently engaged starts to release. At the appro-priate time, the computer begins to apply the other clutch assembly. The computer makes all mechanical operations and decisions to select gears and control the clutches — more on that later.
By having selected a gear and then alternately engaging the multi-friction clutch, the transmission applies torque smoothly to the wheels in the selected ratio. The included figures show the two clutch assemblies.
The outer clutch is called Main Clutch No. 1. This clutch drives the front two gears on the main 1st input shaft. These gears provide the power flow for 1st, 3rd, 5th and Reverse. (Figure 4).
Dacco-ad.indd 7Dacco-ad.indd 7 12/26/06 10:41:52 AM12/26/06 10:41:52 AM
18 GEARS April 2007
Introducing the Volkswagen/Audi Direct Shift 6-Speed Automatic
The inner clutch is Main Clutch No. 2. This clutch drives the rear three gears on the main 2nd input shaft. These gears provide the power flow for 2nd, 4th and 6th. (Figure 5).
The powerflow diagram for each gear range shows the alternating power-flow between the 1st input and 2nd input assemblies. If one clutch fails, the trans-mission will go into failsafe. During failsafe, only certain gears attached to the working clutch are selectable. (Figures 6-8).
Volkswagen and Audi call the mod-ule that controls the transmission the Mechatronics module, and it’s located inside the transmission. For consis-tency, we’ll continue to refer to it as the Transmission Control Module, or TCM. (Figure 9).
The only external wiring to the TCM is power, ground, shifter position, and CAN wiring for data communica-tion with the other computers through-out the vehicle. The TCM includes all the solenoids, actuators, pressure sensors, speed sensors and temperature sensors in the transmission. The TCM is networked to the CAN data bus. This allows it to select the best gear range, based on inputs from the ECM, ABS, gear selector, vehicle electrical sys-tem control module, and steering wheel module (if equipped with steering wheel shift controls). With these controls, the TCM can actuate the hydraulic servos, which will move and hold the sliders to engage a selected gear. When the driver requests a change, or an onboard mod-ule indicates a sufficient change in the vehicle’s operation, the TCM will shift to another gear.
A small, gear-driven oil pump pro-vides all fluid pressure to operate the actuators for the hydraulic servos, apply the clutches, and provide lubrication and cooling, (Figure 10). The TCM is programmed to shift the transmission based on three operating modes: nor-mal, sport and failsafe. In failsafe, the transmission will operate in either 1st and 3rd, or only 2nd gear.
There are a couple additional fea-tures built into the system to make this unit feel more like regular auto-matic transmission. A hill-holding fea-ture under light braking applies both clutches to hold the vehicle from rolling down the hill. If you aren’t pressing the
Figure 2: View of Dual Shaft Input and Secondary Shafts
Figure 3: Geartrain for 1st Input Clutch and Input Shaft
Figure 4: 1st Input Shaft and Engaged Output Shaft Gears;2nd Input Shaft and Engaged Output Shaft Gears
Introducing the Volkswagen/Audi Direct Shift 6-Speed Automatic
brake or accelerator pedal, the vehicle will creep slowly. (Figure 10).
Servicing the 02E is limited to fluid changes, replacing the TCM (Mechatronic module), and overhauling the 1st and 2nd input clutches.
CAUTION: To service the input clutches, you’ll need to remove a large sealing cover from the bellhousing area. Be very careful not to damage it, and don’t even TOUCH either seal surface with your bare hands! The seals and
their surfaces are highly susceptible to damage from the oils in your hands. Use Alignment Tool T10302 to install the seal cover. (Figure 11-12).
Never hold or touch inner seal.Using Alignment tool to Install
This preliminary
information should
help you under-
stand the basic
operation and diag-
nostic strategy for
the 02E direct shift
transmission.
Figure 9
Remember that Old-Time Service?Remember that Old-Time Service?
WIT distributes a complete line of quality new, used, & remanufactured automatic & standard transmission Parts.
Large Sealing Cover. (Figure 12)Use care installing snap ring.
(Figure 13).The unit has a fill and inspection
plug at the bottom of the case. Above the inspection plug is an oil level tube,
similar to the 4-speed 01M units. The manufacturer recommends checking the fluid level with the transmission in park, the engine idling, and the fluid temperature between 70º-100ºF. The fluid is G052 182. A complete fill
is about 7L; draining and refilling will take about 5L. (Figure 14).
CAUTION: Some early model units were made with a filler tube located at the front of the transmission. Don’t fill it there; the electric radiator fan can
Introducing the Volkswagen/Audi Direct Shift 6-Speed Automatic
come on without warning.At this time, there are no indi-
vidual parts available for the (TCM) Mechatronic module or the main gear-box assembly. Please use the following symptom-cause chart to troubleshoot the 02E transmissions.
This preliminary information should help you understand the basic operation and diagnostic strategy for the 02E direct shift transmission. You’ll need the most current software
and CAN-compatible equipment to troubleshoot all the systems and isolate problems from other computers that interact with the TCM. Look for more information as it becomes available.
Figure 12
Figure 13 Figure 14
DEVICE FUNCTION EXPECTED FAILURE
Input RPM (G182) Detects input clutch RPM Multi-clutch slippingMain Drive RPM No. 1 (G501) and 2 No. (G502) Detects mainshaft 1 and 2 RPM If G501 fails, no 2nd; If G502 fails, no 1st or 3rdOutput Shaft Sensors (G195 and G196) Detect output shafts’ rotational To be determined direction and RPMMulti-Clutch Pressure Sensors (G195 and G196) Detects multi-clutch apply pressure If (G193) Fails, only 1st and 3rd; If (G194) Fails, only 2ndTemperature Sensors Input Clutch (G182) Monitors multi-clutch sensor To be determinedTemperature Sensors in TCM (G510 and G93) Monitors oil temperature in TCM Hot reduces engine power. Excessive turns multi-clutches off.Gear Position Sensors (G487-490) Detects position of each Mismatch eliminates one or hydraulic actuator more gears.Main PC Solenoid 3 (N217) Modulates mainline pressure Failure increases mainline, causes harsh shiftsPC Solenoids 1 and 2 (N215) and (N216) Control pressure to each Failsafe either 1st and 3rd, multi-clutch or 2nd onlyPC Solenoid 4 (N218) Controls lube oil to clutches Failure causes harsh shifts. and geartrain
SHIFT SOLENOIDS CONTROLS FAILSAFE IN 1ST AND 3RD, OR 2ND ONLY
No. 1 (N88) 1st and 5th No. 2 (N89) 3rd and Neutral No. 3 (N90) 2nd and 6th No. 4 (N91) 4th and Reverse
