Description & Operation: Differentials

WARNING: This page is about a different car, the 2002 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

The rear axle assembly contains the following features:

Integral-type housing hypoid gear design has centerline of pinion set below centerline of ring gear.
A hypoid ring gear and pinion which consists of a ring gear and overhung drive pinion which is support by 2 opposed tapered roller bearings.
A pinion bearing preload is maintained by a drive pinion collapsible spacer on the pinion shaft and adjusted by the pinion nut.
A rear axle housing assembly which consists of a cast aluminum center section and a stamped-steel rear differential housing cover.
A differential housing cover which uses a silicone sealant rather than a gasket.
An aluminum rear axle housing that must be spread in order to remove the differential case.
A differential case which is a one-piece design with two openings to allow for assembly of internal components and lubricant flow.
A differential pinion shaft which is retained by a threaded differential pinion shaft lock bolt assembled to the differential case.
A differential case which is mounted in the rear axle housing between two opposed differential bearings.
Differential bearings which are retained in the rear axle housing by removable bearing caps.

Differential bearing preload and ring gear backlash are adjusted by differential bearing shims located between the differential bearing cup and the rear axle housing. The use of a pinion depth gauge is required for correct differential ring gear and pinion adjustment.

The axle shafts are held in the differential case by a driveshaft bearing retainer circlip that is located on the inboard CV joint stub shaft pilot bearing housing. When each axle shaft is installed, the driveshaft bearing retainer circlip engages a step in the differential side gear.

The rear axle drive pinion receives power from the engine through the transmission, transfer case, drive shaft and rotary blade coupling (when engaged). The pinion gear rotates the differential case, which is bolted to the differential case outer flange. Inside the differential case, 2 differential pinion gears are mounted on a differential pinion shaft which is pinned to the differential case.

These differential pinion gears are engaged with the differential side gears to which the axle shafts are splined. As the differential case turns, it rotates the axle shafts and rear wheels. When it is necessary for one wheel and axle shaft to rotate faster than the other, the faster turning differential side gear causes the differential pinion gears to roll on the slower turning differential side gear. This allows differential action between the 2 axle shafts.

The rotary blade coupling is not repairable and is installed as an assembly. The mass damper is fastened to the side of the rotary blade coupling and the rear axle housing by 3 bolts. The mass damper dampens vibrations in the rotary blade coupling.