Transmission and Drivetrain: Description and Operation

The All Wheel Drive (AWD) system is available on all Caravan and Voyager models equipped with a 3.3L engine and Ultradrive transaxle. The main benefits of the system are superior straight line acceleration and cornering on all surfaces and better traction and handling under adverse conditions.
The vehicle has mainly front wheel drive characteristics, but when the front wheels start to slip the AWD system takes over. Under normal level road, straight line driving, 90% of the torque is at the front wheels. The viscous coupling allows more torque to the rear wheels based on the slippage of the front wheels.
The Power Transfer Unit (PTU) is attached to a modified automatic transaxle case where the right halfshaft extension housing would normally be located. The PTU provides power to the rear wheels through a hypoid ring gear and pinion seat.
The system consists of five main components: the rear carrier, torque tube, overrunning clutch assembly, a vacuum operated dog clutch and a viscous coupling.