Manual Transmission/Transaxle: Description and Operation
GENERAL DESCRIPTIONCONSTRUCTION AND SERVICING
The transmission provides five forward speeds and one reverse speed by means of three synchronizers 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 is mounted on counter shaft and engaged with counter shaft first gear or second gear, while the high speed synchronizer is done on input shaft and engaged with input shaft third gear or fourth gear.
The fifth speed synchronizer on input shaft is engaged with input shaft fifth gear mounted on the input shaft.
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 transmission 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 counter shaft 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
Movement of gear shift control lever is transmitted to gear shift shaft through gear shift control shaft, and gear shift & select shaft through gear shift arm and gear shift yoke, and then gear shift & select lever to each gear shift yoke, shaft and fork or arm. Gear shift interlock plate is provided to prevent the gear from engaging double.
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 gear is shifted to 5th speed, 5th & reverse gear shift cam turns clockwise with gear shift & select shaft and it is pushed up by cam guide return spring to the position where interlock guide bolt prevents the cam from being shifted to reverse straight.
2. Shifting from 5th to neutral is available and further shift to reverse is interrupted. However, when shift & select shaft is moved to neutral of 3rd-4th position, shift limit cam mechanism is canceled as shown in figure.
3. Selected position in neutral of 5th-REV is shown in figure. While shift & select shaft moves up to allow shift & select lever to shift in 5th or reverse position, shift cam stays because of interference of guide bolt.
4. Now the mechanism is ready to be shifted to reverse without interference of shift cam.