Rear Drive Axle and Differential

WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, and 2011 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

The rear drive axle consists of the following components:

Dished circular flange
Full-time fluid drive coupling
Aluminum housing with steel housing cover
Matched ring and pinion
Conventional open differential
Rubber bushing isolated mounting points
Cover mounted axle vent
Silicone sealant rather than a gasket

The rear drive axle is serviced as follows:

The active torque coupling is installed new as an assembly with the rear axle
The pinion seal and the differential halfshaft seals are the only serviced components of the rear drive axle. If other components of the rear drive axle are worn or damaged, the assembly must be installed new

The rear axle drive pinion receives power from the engine through the transaxle, Power Transfer Unit (PTU), driveshaft and active torque coupling, and is engaged ON DEMAND. The pinion gear rotates the differential ring gear, 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 case. These differential pinion gears are engaged with the splined differential side gears. The halfshafts are held in the differential side gears by a retainer circlip that is located on the inboard CV joint stub shaft. When each halfshaft is installed, the retainer circlip engages a step in the differential side gear. There are no stub shaft bearings in the differential housing. As the differential case turns, it rotates the halfshafts and rear wheels. When it is necessary for one wheel and halfshaft 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 halfshafts.