A hydrostatic transmission for a working machine having a frame, an engine on the frame, and at least one wheel driven by the hydrostatic transmission is disclosed. The hydrostatic transmission includes a housing, a hydraulic pump, the hydraulic pump driven by an output shaft from the engine, a hydraulic motor for driving an output shaft connected to the at least one wheel, a first fluid line fillable with hydraulic fluid to be maintained under a first pressure, a second fluid line fillable with hydraulic fluid to be maintained under a second pressure, a first check valve for allowing hydraulic fluid to enter the first fluid line, a second check valve for allowing hydraulic fluid to enter the second fluid line, and an entrained air deflector for preventing hydraulic fluid entrained with air from entering the first check valve and the second check valve.