'83 Trojan 10m transmission

[gmileskiy]

Can anyone tell me something about this transmission, or where I can learn about it? I have twin 350s in a fly-bridge cruiser and blew a starboard trans last fall (forward, but no reverse).
I had it re-built by the marina boat repair shop, but after it was installed, even though it apparently worked, eventually, in idle I noticed that it would not fully disengage from forward - that is, in neutral at dock, it continued to turn the prop. When I complained to the repair mechanic, he indicated he would have to pull it again, and check it out.
Now, I have been spending all summer trying to get it repaired. He says he tried replacing the clutch pack (didn't work) and now says he has to "replace the piston" in it. Now I'm waiting on him trying that - does this make sense?
Does anyone have any diagrams or drawings of the insides of these? It's supposed to be a Borg Warner "Velvet drive", but that's all I know for now.
Any suggestions on how I can get a little smarter on this?

[prowlersfish]

Info here
http://www.trojanboats.net/wforum/viewt ... =1&t=4263g

Most likely your forward clutch pack is dragging That can be from the clutch pack being to tight / warped plates ,Internal seal leaks apply piston sticking or even a shift valve issue . A slight drag is not that abnormal where the shaft turns a little .

[Flyboy]

+1 to Prowlersfish, sounds like the forward plates are dragging a bit. Mine drag a little, idling in the slip the boat will move forward. There is a spec for clearance in the forward clutch pack, depending on how much drag you have, you may be a bit out of spec. If it is the clutch pack it will eventually improve.

[BobCT]

I would disconnect the linkage and manually shift it into neutral on the transmission and see if it changes. It's easy to have the linkage adjusted wrong and and neutral won't be fully disengaged. It should basically "fall" into place (cable end onto trans linkage ball.

If this has been the issue for a while it might be too late if the clutches are warped. I'm sure it's a Velvet Drive 72c. There are manuals floating around. The 71c is older but is very close if you just need general knowledge.


Bob

[Paul]

A slight drag is not that abnormal where the shaft turns a little .

+1 on this. When my engine is first started and the transmission is cold, the shaft will turn a bit slowly (in neutral). Once the trans warm up it stops.