I have a Merctrans MCM-E with a TRS stern drive that's stuck in forward gear regardless if the remote control is in neutral or reverse positions. I have removed the shift control housing to check the operation of the piston by blowing compressed air into one of the oil inlets and it was moving freely. Does anyone have a service manual that I can download or any suggestions why it's stuck in forward?

Looks as the trans is in Merc manual 2 (I don't have it) but in the thread below member pickelnjim indicated he did

Merctrans 2 rebuild.

Is the shifter going into the trans moving ? When it happened to me I thought the shifter was moving, but only the elec relay was.

Convert it to cable shift. The electric will have it in 2 gears and burn it up.

It looks like it's hydraulically controlled. The shift cable is connect to the link that controls a plunger inside the control valve assembly through hydraulic pressure. The plunger then pushes against a bar of the clutch band. There's nothing electric around the shifting mechanism except for the neutral safety switch.

It's a shift cable connected to the valve control assembly. Not electrically controlled.

That is all for reverse that your messing with. The band locks down on the planetary stopping it which causes the output shaft to spin in reverse. For forward the fluid flows a different path to the piston which applies pressure to the clutch pack locking it up for forward. Sounds like your clutch pack is all stuck together or plates are all warped. Clutch drive plates and steels are from a Ford FMX trans as well as a few other parts and easily obtainable. Engine and Trans is gonna have to come out. Send me an email address and I'll hook ya up with the needed service manual. Jim

[email protected] Thanks Jim!