tilt motor on my baot is dead but hydraulics are good, I have a used complete spare unit (pump, motor, pistons etc with a working motor). I'd like to just replace the motor since condition of hydraulics on the spare unit are unknown. Can I just swap motors, where would I get a diagram or directions, do I pull the pump and motor then reattach the pump and put back on or can I remove the motor only and leave the pump in the base ? is this possible with 4 screws on top ? can I reuse seals ?