Rear Drive Unit
| ITEM | DESCRIPTION |
|---|---|
| 1 | Speed sensor |
| 2 | Breather |
| 3 | Breather pipe |
| 4 | Output seal |
| 5 | Left Rear Drive Unit (RDU) clutch drive motor |
| 6 | All Wheel Drive Control Module (AWDCM) |
| 7 | Input seal |
| 8 | Oil filler plug |
| 9 | Output seal |
| 10 | Oil drain plug |
The Rear Drive Unit (RDU) is attached to the rear subframe.
The housing comprises the following:
- A crown wheel drive gear and differential.
- A pinion drive gear and shaft.
- A wet multiplate clutch pack.
- An electronically controlled ball ramp.
The All Wheel Drive Control Module (AWDCM) 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 pack. 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 standard driveline there are 2 halves of the housing. The left section is common with the active driveline RDU and houses the clutch.
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 drive gear has a splined shaft at 1 end to interface with the clutch pack. The crown wheel drive gear has a differential at he other end.
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 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.
The RDU drives the rear halfshafts and wheels through a wet multiplate clutch. This clutch can disconnect the All Wheel Drive (AWD) system at the halfshaft interface to the RDU. The dog clutch in the Power Transfer Unit (PTU) and the RDU are controlled by the All Wheel Drive Control Module (AWDCM). The AWDCM is designed to constantly monitor vehicle dynamics. The AWDCM disconnects during steady-state driving speeds above 25 km/h (15 mph) and automatically reconnects (within 300 milliseconds) when required.