Manual Transmission/Transaxle: Description and Operation

Manual Transaxle Construction








The transaxle provides five forward speeds and one reverse speed by means of three synchronizer mesh devices and three shafts-input shaft, countershaft and reverse gear shaft. All forward gears are in constant mesh, and reverse uses a sliding idler gear arrangement. The low speed synchronizer mesh device is mounted on countershaft and engaged with countershaft first gear or second gear, while the high speed synchronizer mesh device is done on input shaft and engaged with input shaft third gear or fourth gear. The fifth speed synchronizer mesh device on input shaft is engaged with input shaft fifth gear mounted on the input shaft. The double cone synchronizing mechanism is provided to 2nd gear synchromesh device for high performance of shifting to 2nd gear.
The countershaft turns the final gear and differential assembly, thereby turning the front drive shafts which are attached to the front wheels.
For servicing, it is necessary to use genuine sealant or its equivalent on mating surfaces of transaxle case which is made of aluminum. The case fastening bolts must be tightened to specified torque by means of torque wrench. It is also important that all parts are thoroughly cleaned with cleaning fluid and air dried before reassembling.
Further, care must be taken to adjust preload of countershaft taper roller bearings. New synchronizer rings are prohibited from being lapped with respective gear cones by using lapping compound before they are assembled.

Gear Shift Mechanism








The gear shifting control system consists of following main parts. Movement of gear shift control lever is transmitted to gear shift & select shaft through gear shift and gear select cables.

5th & Reverse Gear Shift Cam





5th & reverse gear shift cam, cam guide return spring and 5th to reverse interlock guide bolt are provided to prevent the gear from being directly shifted from 5th to reverse.








1. When shift lever is at neutral position between 3rd and 4th gear, shift cam (2) is under guide bolt and can turn freely clockwise (to 3rd gear) and counterclockwise (to 4th gear).





2. When shift lever is shifted toward the right from neutral position, shift and select shaft (1) moves up but shift cam (2) is restricted by guide bolt and return spring is contracted.








3. When shift lever is shifted to 5th gear, shift & select shaft (1) turns clockwise letting shift cam (2) off from guide bolt and pushed up by return spring. In this state, movement of shift cam is restricted by guide bolt and therefore, gearshift to reverse is not attainable.





4. When shift lever is shifted from neutral position between 5th gear and reverse gear to reverse gear, shift cam (2) turns counterclockwise to attain reverse gear.