A secondary drive unit (SDU) for the secondary axis of an all wheel drive vehicle consists of an SDU housing defining a first section for receiving a main shaft which is connected to a drive source and a second section for enclosing a twin clutch assembly. The twin clutch assembly has a common clutch housing connected to the main shaft, a left clutch for selectively connecting a left output shaftand the clutch housing, a right clutch for selectively connecting a right output shaft and the clutch housing, and a rigid center plate separating the left and right clutches. The twin clutch assemblymay be activated by a dual action piston assembly to decrease all wheel drive synchronization and connection response times.