Abstract: A transfer case adapted for installation on a front-wheel drive vehicle having a transversely oriented engine and transaxle receives drive torque on a transferse axis and provides it to the rear differential on a longitudinal axis. The transfer case is driven through the front axle center differential cage. A drive chain delivers power through sprockets to a modulating or viscous clutch disposed behind and parallel to the front stub axles. The output of the clutch is provided to a bevel gear set which drives the rear prop shaft, rear differential and rear axles. The transfer case and rear prop shaft are preferably disposed along the longitudinal center line of the vehicle. Alternatively, the transfer case and the rear prop shaft may be disposed along an axis laterally offset but parallel to the longitudinal center line of the vehicle.

Abstract: A modulating clutch for disposition and use in a motor vehicle drive train includes a disc pack clutch assembly and clutch actuator. The clutch actuator includes an assembly for generating compressive force which is applied to the clutch pack assembly and a preload member which partially engages the clutch pack to provide torque transfer up to a predetermined level without activation of the clutch actuator. Activation of the clutch actuator increases the torque transfer or throughput above the predetermined level. The differential of the present invention thus functions passively as a limited slip differential by allowing torques in excess of the predetermined torque level to slip each axle relative to the driveline input thereby provide a constant, minimum level torque coupling between the driveline and each axle. When the clutch actuator is energized, it may be utilized to control torque transfer at levels above the predetermined level between the input and output of the clutch mechanism.