Rear Drive Unit
| ITEM | DESCRIPTION |
|---|---|
| 1 | Right Rear Drive Unit (RDU) clutch drive motor |
| 2 | Speed sensor |
| 3 | Breather |
| 4 | Breather pipe |
| 5 | Left RDU clutch drive motor |
| 6 | All Wheel Drive Control Module (AWDCM) and AWDBCM |
| 7 | Input shaft |
| 8 | Oil filler plug |
| 9 | Oil drain plug |
The Rear Drive Unit (RDU) comprises a main housing and left and right covers. The housing comprises the following:
- A crown wheel drive gear and differential.
- A pinion drive gear and shaft.
- There are 2 wet multiplate clutch packs.
- there are 2 electronically controlled ball ramps.
The All Wheel Drive Control Module (AWDCM) and AWDBCM is located externally on the housing.
The oil in the housing lubricates the pinion and crown wheel drive gears and bearing and also lubricates and cools the multiplate clutch packs. A filler/level plug is located on the rear of the housing and a drain plug is located on the underside of the housing.
On active driveline there are 2 halves of the housing, containing the clutches.
The crown wheel drive gear is mounted longitudinally across the RDU on a crown wheel shaft. The drive gear is a low offset hypoid bevel gear configured for minimal power loss across the speed range. The crown wheel is welded to a tube-shaft which is splined at each end to provide drive to the clutch packs.
The crown wheel shaft is supported on opposing taper roller bearings which are preloaded by the outer housings.
The pinion drive gear and shaft is locked in the housing at 90° to the crown wheel drive gear. The pinion drive gear shaft is supported in the housing on opposing taper roller bearings. The pinion drive gear shaft is retained in the housing with a preload nut. The outer end of the pinion gear is splined and mates with the driveshaft in a Direct Torque Flow (DTF) connection.
A collapsible spacer is located between the taper roller bearings. The collapsible spacer holds the taper roller bearings in alignment and also collapses under pressure applied by the preload nut. This allows the preload nut to be tightened to a predetermined torque, which collapses the spacer. This sets the correct taper roller bearing preload and the correct meshing of the teeth of the pinion and the crown wheel drive gear.