Tranny Trouble MD11C

[Barry]

Looking at rebuild options for the MSB reverse gear on my Volvo MD11C, any advice?? Hard to find reverse, forward seems fine.

Thanks

[Brian]

Looking at rebuild options for the MSB reverse gear on my Volvo MD11C, any advice?? Hard to find reverse, forward seems fine.

Thanks

Barry,


We rebuilt the transmission on our MD11 two years in a row. Reverse was also the issue. An internal cone (insert technical term here-it's been a while) in the transmission needed replacement. Apologies for not recalling all the details, but I seem to recall this part can fail after a while.


But we then had to rebuild it the next season and we knew something was wrong. I can't recall if the two problems were related, but we couldn't get it in reverse again. One thing we noticed, and you know something is definately wrong here, is that when we looked in the engine compartment (from the opening in the port locker on our 33) you could see the prop shaft inching it's way towards the back of the boat. An internal component had broken so the prop was actually pulling the shaft out (fittings insided kept if from coming all the way out) to the point the gears were no longer together and therefore, no movement. When it was put back in forward the prop "drove" the shaft back in, and you could actually get some forward movement with the boat.


Well something was "cracking" the transmission inside. The motor mounts all checked out. It wasn't until after the engine was pulled that it was determined the threads in the engine bed had stripped. So while the mounts looked good, and all seemed fine at rest with the weight of the engine on them, once it was underway the only real firm "mount" was the prop shaft through the cutless bearing. And the bearing was showing wear as well, as one might expect. All this stress on the shaft made it crack the transmission inside as the heavy engine shook around it. And of course the boat exhibited more vibration than normal.


Anyway, the replacement part inside the tranny was $600. Then there would be a few hours of labor to replace it. With the engine bed fixed we'd be good as new.


But after two years of trying to diagnose this problem we thought it might be a good time to repower since the engine was already out. not a cheap ordeal, but new yanmars sure run smooth and quiet. so now we have an MD11 at the house that runs great, but just needs a rebuilt transmission.


don't know if that was helpful at all, but thought I'd share our experience in case any aspects were similar.


regards,


brian