Differential Assembly: Description and Operation

Differential:

DESCRIPTION
The rear driveline module assembly (Fig. 1) consists of four main components:
- Bi-Directional Overrunning Clutch (BOC)
- Viscous Coupling
- Differential Assembly
- Torque Arm

The viscous coupling and bi-directional overrunning clutch are contained within an overrunning clutch housing, which fastens to the differential assembly. The overrunning clutch housing and differential assembly have unique fluid sumps, each requiring their own type and capacity of fluid. The overrunning clutch housing requires Mopar ATF+4 (Automatic Transmission Fluid-Type 9602) or equivalent. The differential assembly requires

Driveline module service is limited to the following components:
- Differential Assembly (serviced only as assembly)
- Viscous Coupling
- Bi-Directional Overrunning Clutch (BOC)
- Overrunning Clutch Housing
- Seals Input Flange, Output Flange, Overrunning Clutch Housing O-rings)

OPERATION
The primary benefits of All Wheel Drive are:
- Superior straight line acceleration, and cornering on all surfaces
- Better traction and handling under adverse conditions, resulting in improved hill climbing ability and safer driving.

The heart of the system is an inter-axle viscous coupling. The vehicle retains predominantly front wheel drive characteristics, but the All Wheel Drive capability takes effect when the front wheels start to slip. Under normal level road, straight line driving, 100% of the torque is allocated to the front wheels. The viscous coupling controls and distributes torque/power to the rear wheels. The viscous coupling transmits torque to the rear wheels, in proportion of the amount of the slippage at the front wheels. This variable torque distribution is automatic with no driver inputs required. The coupling is similar to a multi-plate clutch. It consists of a series of closely spaced discs, which are alternately connected to the front and rear drive units. The unit is totally sealed and partially filled with silicone fluid. There is no adjustment, maintenance or fluid checks required during the life of the unit.

The overrunning clutch allows the rear wheels to overrun the front wheels during a rapid front wheel lock braking maneuver. The overrunning action prevents any feed-back of front wheel braking torque to the rear wheels. It also allows the braking system to control the braking behavior as a Two Wheel Drive (2WD) vehicle.

The overrunning clutch housing has a separate oil sump and is filled independently from the differential. The fill plug is located on the side of the overrunning clutch case. When filling the overrunning clutch with lubricant use Mopar ATF+4 (Automatic Transmission Fluid-Type 9602) or equivalent.

The differential assembly contains a conventional open differential with hypoid ring gear and pinion gear set. The hypoid gears are lubricated by SAE 80W-90 gear lubricant.