A drive system designed to use a vehicle's existing hydraulic system to operate a controllable limited slip differential assembly. The limited slip differential assembly may be associated with the front axle, the rear axle, or the driveline between the front and rear axles. The differential assembly may also be used in combination that includes front, rear, or intermediate differential assemblies. The drive system further includes a friction clutch assembly for selectively engaging and disengaging an input member with an output member of the differential assembly, a fluid clutch actuator for selectively frictionally and variably loading the clutch assembly, and a fluid pump that is a common source of pressurized fluid for the fluid clutch actuator and the existing hydraulic system of the motor vehicle other than the fluid clutch actuator of the drive system. The fluid clutch actuator is actuated by fluid pressure generated by the fluid pump.