Aftermarket Hydraforce HS50-42-P Hot Oil Shuttle Valve Replacement Part Number: HS50-42-P, HS5042PF eature:The HS50-42 is a screw-in, cartridge style, spool type, closed in transition, 2-position, 3-way hot oil shuttle valve for use with general purpose hydraulic fluids. The valve CAN be utilized on hydrostatic transmissions to direct charge pump oil to a heat exchanger or to tank.