| Description and Operation The hydraulic control of all the shift valves in the automatic transaxle is electronically regulated by the automatic transaxle control module. The drive ratios are achieved through two planetary gear sets, three clutches and two clutch plate assemblies. The power is transferred through the planetary gear sets via the output shaft to the differential. The torque converter is equipped with a lock-up clutch. The lock-up clutch is engaged as determined by the engine load and vehicle speed, and provides a mechanical link for gears 1 to 4. The selector lever can only be moved out of the park position when released by an electromagnetic switch which is actuated by the application of the foot brake. In addition, this lock is indicated by a warning indicator in the instrument cluster which extinguishes when the brake pedal is depressed. An ignition key lock in the ignition switch ensures that the ignition key cannot be removed except when the selector lever is in the "P" (Park) position. The timing of gear changes is established by the transaxle control module using fuzzy logic, and depends on the driving situation and the vehicle resistance to motion. The advantage is to provide gear changing according to need, matching the point of change individually in all driving situations. Extra gear change mapping is carried out automatically on vehicle assent or descent to optimise the gear change point, taking into account the accelerator pedal position and vehicle speed. Gear change mapping for extreme ascents is matched to the engine output. Gear change mapping for extremely steep descents is matched to the engine braking force. The oil pump is driven by the torque converter. It is important to be aware of the identification letters and classifications when carrying out repairs.
For additional information, refer to Specifications in this section.
New torque converters are equipped with an integrated needle roller bearing on the turbine shaft. The fourth identification letter of the new converters is D, H or J. Previous torque converters with plain bearings are identified by B, C; R, T or V as fourth letter. Automatic transaxle Automatic transaxle identification Identification letters and build date of the automatic transaxle - Example: CYF 18 01 5
- CYF = Identification letters
- 18 = Day
- 01 = Month
- 5 = year of manufacture (1995)
Torque converter identification For additional information, refer to Specifications in this section. Overview — valve body (1) 3 – Fluid pan retaining bolt 9 – Valve body assembly retaining bolt 12 – Electrical connector retaining bolt 18 – Manual selector plunger actuating rod Overview — valve body (2) Overview — clutch and planetary gear input shaft 2 – Measuring and adjusting shims 5 – Direct and overdrive clutch assembly with turbine shaft 6 – Thrust bearing and shim 7 – Planetary gear input shaft 9 – Needle roller thrust bearing 10 – Annulus gear input shaft 11 – Needle roller thrust bearing 12 – Needle roller thrust bearing washer 14 – Needle roller thrust bearing 15 – Needle roller thrust bearing washer 16 – Transaxle housing with installed one-way clutch and circlips 19 – Planetary gear input shaft retaining bolt Overview — low and direct clutch 3 – Clutch plate assembly circlip Overview — reverse gear clutch 1 – Clutch plate assembly circlip 10 – Clutch hub and ball valve Overview — direct and overdrive clutch with turbine shaft 1 – Clutch plate assembly circlip 5 – Thrust plate with compression spring (the caulked compression spring faces the servo piston) 10 – Clutch hub with turbine shaft Overview — one-way clutch, reverse clutch plate pack, and planetary gear 1 – Clutch plate cage circlip 10 – Planetary gear set O-ring 11 – Needle roller thrust bearing shim 12 – Needle roller thrust bearing 13 – Needle roller thrust bearing shim 14 – Planetary gear output wheel Overview — one-way clutch 5 – Reverse clutch servo piston Overview — differential bearings 2 – Speedometer drive pinion with carrier 3 – Vehicle speed sensor (VSS) 4 – Front right-hand intermediate driveshaft extension oil seal 7 – Torque converter housing 11 – Differential tapper roller bearing 12 – Automatic transaxle housing 13 – Intermediate shaft oil seal 15 – Front left-hand intermediate driveshaft Overview — differential 5 – Differential housing retaining bolt Overview — planetary gear and output wheel 4 – Outer taper roller bearing 7 – Needle roller thrust bearing 9 – Inner taper roller bearing 10 – Planetary gear output wheel Overview — parking lock assembly 2 – Output shaft drive gear 6 – Output shaft bearing cover 8 – Parking pawl gear wheel 14 – Support plate retaining bolt 17 – Selector shaft oil seal 18 – Selector shaft lock washer 19 – Selector shaft retaining bolt 20 – Detent spring retaining bolt 22 – Detent spring retaining bolt 24 – Selector shaft expanding collet Overview — output shaft 1 – Output shaft bearing housing 5 – Output shaft taper roller bearing 8 – Output shaft needle roller bearing Sequential shifting From MY 2001, the 4-speed automatic transaxle is equipped with a sequential shift function. With this, the gears can be selected manually. For additional information, refer to Section 307-05 Automatic Transmission/Transaxle External Controls. The transaxle itself remains unchanged. There are only a few new components and changes to the transaxle control module: - Gear indicator display in the instrument cluster
- New shift alley with selector lever
- Revised automatic transaxle control module
Solenoid valves Three shift solenoid valves SS1, SS2 and SS3 are used to obtain gear ratios. The shift solenoid valve SS4 activates the lock-up clutch modulation valve. The shift solenoid valves SS5 and SS6 are supplementary valves which affect selection changes and are only controlled during gear changes. The subsequent table indicated which clutches and bands are activated in the individual gears. Reference Table: Clutch and Band Application | Gear | Reverse Band | 2/4 Band | 1/3 Clutch | Reverse Clutch | 2/4 Clutch | One-Way-Clutch | Torque Converter Clutch | | R | X | | | X | | | | | 1H | | | X | | | X | | | 1M | | | X | | | X | X | | 2H | | X | X | | | | | | 2M | | X | X | | | | X | | 3H | | | X | | X | | | | 3M | | | X | | X | | X | | 4H | | X | | | X | | | | 4M | | X | | | X | | X | H = hydraulic, M = mechanical, X = clutch/band is engaged | 
