Transfer Case: Description and Operation

The All Wheel Drive system available on Tempo and Topaz models, is intended to provide increased on the road traction and has ``shift on the fly'' capability. It can be shifted into or out of the all wheel drive mode at any speed as well as when the vehicle is standing still, by using an on/off toggle switch. The main components of this system are a transfer case, rear drive axle, half shafts and driveshaft assemblies.

The transfer case used on Tempo and Topaz models with the All Wheel Drive system, is actuated by an electrically controlled vacuum servo system. When the AWD (All Wheel Drive) switch is turned on, a relay activates the 4WD solenoid valve. The 4WD solenoid valve allows a vacuum to be created in the lefthand chambers of the vacuum servo. Vacuum in the lefthand chambers moves the servo rod and sliding collar into engagement with the transfer case output gears, driveshaft and rear axle. When the AWD switch is turned OFF, a relay activates the 2WD solenoid valve. The 2WD solenoid valve then allows a vacuum to be created in the righthand chambers of the vacuum servo. Vacuum in the righthand chambers then returns the servo rod and sliding collar, disengaging the transfer case, driveshaft and rear axle output gears.