Abstract: A hydraulic pump forces fluid from a sump supplied from a lubrication circuit and a cooling circuit that takes heat from an electric motor. The lubrication circuit is supplied with fluid directly from the discharge side of the pump and is returned directly to the sump. The cooling circuit, disposed in parallel arrangement with the lubrication circuit, has its volumetric flow rate from the discharge side of the pump controlled by a bimetallic valve, which opens and closes in accordance with the temperature of the fluid. When fluid temperature is low, the pump discharge is fully opened both to the lubrication circuit and the cooling circuit. When fluid temperature is relatively high, the pump discharge is directly entirely through a heat exchanger which transfers heat to a cooling air stream, and the fluid exiting the heat exchanger is delivered to the cooling circuit. The speed of the pump is controlled in accordance with a signal produced by a temperature sensor mounted on a traction motor.