Rear Drive Axle and Differential

WARNING: This page is about a different car, the 2007 Lincoln Mark LT and 2007 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.

The rear axle assembly consists of the following:

Semi-floating axle shafts carrying the weight of the vehicle through the axle shaft bearings
Integral-type housing hypoid gear design (center of the pinion set below the centerline of the ring gear)
Hypoid differential ring gear and pinion consisting of an 10.25-inch ring gear and an overhung drive pinion that is supported by 2 opposed tapered roller bearings
Pinion bearing preload that is maintained by a drive pinion collapsible spacer on the differential pinion shaft and adjusted by the pinion nut
Cast center section with 2 steel tube assemblies and a stamped differential housing cover
Differential housing cover using silicone sealant as a gasket
Differential pinion shaft that is retained by a threaded differential pinion shaft lock bolt attached to the differential case
Differential case that is mounted in the rear axle housing between 2 opposing differential bearings that are retained in the rear axle housing by 2 removable bearing caps
Differential bearing preload and ring gear backlash which are adjusted by differential bearing shims that are located between the differential bearing cups and the rear axle housing
Rear axle identification that is on an embossed metal tag bolted to the differential housing cover

The rear drive axle receives rotational torque from the driveshaft. The direction of the rotation determines movement of the vehicle. The rotation enters the rear drive axle through the drive pinion flange, turning the drive pinion and rotating the ring gear. The ring gear is bolted to the differential case. The differential case houses the pinion shaft holding the differential pinion gears. The pinion gears are in mesh with the differential side gears splined to the axle shafts. It is the unique arrangement of the differential gearing that allows the axle shafts to be driven at different speed when needed, such as when driving around corners. A Traction-Lok® differential is also available that introduces a series of clutch plates and discs behind the differential side gears to deliver as much torque as possible to each axle shaft when the traction at the rear wheels is not equal. The Traction-Lok® differential requires a friction modifier that must be installed with the axle lubricant for the plates and discs to be functional.