Abstract: A pilot control system for maintaining a constant operating hydraulic fluid pressure in a hydraulic system throughout a range of hydraulic fluid flow and temperature conditions. The pilot control system has a pilot pump and a pilot relief valve in fluid communication with the pilot pump. A first pressure reducing valve is in fluid communication with the pilot pump and the pilot relief valve so as to reduce the pressure to components downstream of the pressure reducing valve.

Abstract: A cooling fan drive system for connecting a charge pump to an output of a cooling fan motor. This arrangement allows hydraulic fluid to be suctioned into the charge pump when the charge pump is remote from a hydraulic tank. The cooling fan drive system has a hydraulic tank that stores hydraulic fluid. A cooling fan pump is connected between the hydraulic tank and a cooling fan motor. A connector is connected between the cooling fan motor, the charge pump and the hydraulic tank. This arrangement allows flow of hydraulic fluid from the cooling fan motor to the charge pump.