Overdrive Assembly: Description and Operation

13. REDUCTION GEAR





Engine power is transmitted from the rear planetary carrier to the reduction drive shaft and the reduction drive gear. In an FWD vehicle, power is then transmitted to the final gear through the reduction driven gear and drive pinion. In a AWD vehicle, power transmission to the front wheels is the same as an FWD vehicle. Power to the rear wheels is transmitted from the transfer clutch hub, Welded to the side of the reduction drive gear, and passes through the transfer clutch (multi-plate clutch), to the rear drive shaft propeller shaft rear differential rear wheel.

14. FINAL REDUCTION GEARS
General
The hypoid drive gear is mounted to the cast iron oil pump housing by double taper roller bearings. The hypoid driven gear and the differential are mounted to the differential case. Both ends rotate and are supported by taper roller bearings in the converter case.





Hypoid Gear
The front end of the drive pinion shaft is supported by the double-taper roller bearing on the oil pump housing. The rear end is supported by two roller bearings on the transmission case and extension case. The double-taper roller bearing is preloaded by tightening the lock nut to a specified torque via the collar. The tooth contact of the hypoid gear is adjusted by changing the shim thickness between the double-taper roller bearing flange and oil pump housing.
The rear end of the drive pinion shaft is spline-fitted to the reduction driven gear, which is secured with a lock nut. The external helical spline has some lead, and the reduction driven gear is forcefitted to this shaft end.





Differential Gear





The differential bevel gear is locked to the axle shaft by a clip.





Speedometer Gear
The speedometer drive gear is mounted directly on the differential case, and the speedometer driven gear is mounted to the torque converter case. With this arrangement, the speedometer drive and driven gears are properly lubricated.