As an option in 1991, Chrysler offered All Wheel Drive (AWD) on Caravan/Voyager models. These models are basically the same as the front wheel drive versions, with the exception of the components needed for driving the rear wheels as well.
The power is transferred to the rear wheels through the Power Transfer Unit (PTU) attached to the transaxle. The power travels through the PTU to a torque tube that contains the center driveshaft. The power then enters an overrunning clutch assembly, attached to the front of the rear differential carrier.
The overrunning clutch assembly is separate from the rear carrier. The overrunning clutch assembly has an vacuum operated dog clutch, it is lubricated with Mopar ATF type 7176. The rear carrier is lubricated with SAE 85W-90 gear lube.