Front Drive Axle and Differential
The front drive axle consists of:
- A Salisbury axle design with final drive components assembled into a one-piece housing
- A hypoid gear design with the centerline of the pinion set above the centerline of the ring gear
- Two opposed tapered roller bearings support the drive pinion in the axle housing
- Removable differential bearing caps retain the differential assembly in the axle housing
- U-joints with zerk fittings in the axle shafts
- Full-floating axle shafts
- A cast center section with 2 steel tubes
- A stamped differential housing cover
- Silicone sealant is used as a differential cover gasket
- Axle identification is found on an embossed tag bolted to the differential cover
- A drive pinion collapsible spacer, located on the pinion shaft, maintains pinion bearing preload. The pinion nut adjusts the preload
The front drive axle receives input from the transfer case by way of the front driveshaft. Rotational torque is transferred through the drive pinion to the ring gear, which in turn drives the differential case. Inside the differential case are the pinion gears which rotate on the stationary pinion shaft and the side gears which are splined to the axle shafts. The differential assembly is a gear arrangement that allows the drive wheels to be driven at different speeds and divides the input torque of the pinion gear between the axle halfshafts. The front axle transmits torque only and carries no vehicle load. U-joints located near the wheel knuckle in the axle shafts, allow the axle shafts to remain stationary in relationship to the side gears, yet articulate at the knuckle. These U-joints permit the wheels to be driven and turned at the same time. Lack of lubrication is among the most common causes of U-joint concerns. It is essential that all bearing seals be purged of old grease and contaminants.