Rear Drive Unit (RDU)
WARNING: This page is about a different car, the 2008 Mercury Sable, 2008 Ford Taurus X, and 2008 Ford Taurus. However, it is still accessible from the selected car via links, so may be relevant.
The active torque coupling/Rear Drive Unit (RDU) is serviced as an assembly.
The RDU housing cover uses a silicone sealant rather than a gasket.
Each halfshaft is held in the RDU case by a driveshaft bearing retainer circlip that is located on the inner CV joint stub shaft pilot bearing housing. When each halfshaft is installed, the driveshaft bearing retainer circlip engages a slot in the RDU side gear.
The RDU operates as follows:
- The RDU pinion receives power from the engine through the transaxle, transfer case, driveshaft and ATC, and is always engaged.
- The pinion gear rotates the 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 that is pinned to the differential case.
- These differential pinion gears are engaged with the differential side gears, to which the halfshafts are splined.
- 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.