A power transfer unit for an all-wheel drive drivetrain that includes an engine, a transmission having a pump for circulating hydraulic fluid from a sump, and a driveshaft. The power transfer unit includes an input for receiving driving power from the transmission, an output for delivering driving power to the driveshaft, a first clutch, a first fluid supply path for delivering the hydraulic fluid from the pump to the first clutch, and a fluid return path for retuning the hydraulic fluid from the power transfer unit to the sump of the transmission.