50 hp honda. unit working fine going down but doesn't want to raise (extend). Had another unit, changed the pump. both pressure relief valves each end of plunger,changed the plunger also and the plunger sleeve. It looks as I did changed every mobile part. when closing the pump sound is loading normal but doesn't sound loading when going the other way. If I pull on the shaft when the extend action is going the cylinder extend slowly but absolutely no torque. Any idea