Abstract: A hydrostatic transmission is provided of the type including a pump (15), a motor (17), and a pintle assembly (35) defining high (61) and low (63) pressure fluid conduits. In communication with the conduits, the pintle assembly includes a pair of acceleration valves (85, 89), each of which comprises a differential area piston. Adjacent each acceleration valve is a pilot valve means (95) disposed in a pilot bore (105) and including a valve member (115) operable, in response to system pressure in excess of the pressure relief setting of a spring (117) to relieve fluid pressure in a chamber (101), such that the acceleration valve (85) is biased toward an open position (FIG. 5) relieving fluid pressure spikes from the high pressure conduit (61) to the low pressure conduit (63).