A system for providing auxiliary power comprises a primary circuit including a primary pump, an output line for providing primary power, and a return line. An auxiliary circuit includes an auxiliary pump, an output line for providing the auxiliary power and a return line. The auxiliary circuit also includes a valve for controlling fluid flow in the output and return line of the auxiliary circuit. A reservoir is connected to the primary return line and to the auxiliary return line. A controlled leakage apparatus for cooling the auxiliary pump is connected to the auxiliary circuit, the reservoir and the primary circuit, and in response to a predetermined pressure in the primary circuit directs a portion of auxiliary output fluid to the reservoir. Approximately all of the auxiliary output fluid is directed to the auxiliary output line when the primary circuit provides less than the predetermined pressure. The auxiliary circuit includes a drive apparatus connected to a vehicle for operating the auxiliary pump whenever the vehicle is moving.