Reversing gear problem

[Wisakedjack]

I went to the boat today and tried to fix the coupling. I took the shaft key out of the coupling and it appeared to be in good condition. I then tried to install the coupling on the shaft as was suggested in the thread. I only managed to wiggle it in half way. I then took the key out and tried it without the key with the same result. I am wondering what may be preventing the coupling to get into the right place?

The only think that comes to mind is draining the oil and then removing cover that is held in place by 6 bolts on the aft side of transmission. May be then I can see better what the problem is. Does this sound reasonable? I know it may sound crazy, but is it possible for the whole transmission assembly to slide aft over the transmission shaft? Can anyone think of anything else I could try to do? I would greatly appreciate any suggestions. Thanks.

[hanleyclifford]

Referring to the picture on post #22 notice the bearing off to the side. Now see the forward end of the coupling. The coupling has to go inside of the inner race of that bearing while also slipping over the shaft while remaining aligned with the keyway (no twisting allowed). This is what you are up against and if there are any burrs or glaze the task can be daunting. Because your coupling slipped off while in service the possibility exists for slight damage or irregularities on any of the relevant surfaces. You may well have to remove the bearing and clean and deburr the inner race which you cannot see right now. Here's that picture again:

[Wisakedjack]

Here is an update on my gear issue. I went to the boat today and took another look at the output coupling. Turned out that the coupling had a crack (see picture below):



The crack is pretty much aligned with the key groove on the inside. I guess this explains why I could not insert the coupling into the bearing. Guess, I will need to get a new output coupling from MM.

As an experiment I tried to smooth the crack and see if the coupling could be inserted into the bearing without the key. I did not succeed, so may be the bearing has some irregularities as well. I took the cover on the aft of gear box and took a look at the bearing. It rotates freely and the key groove looks ok (see picture below):



But obviously I can't tell whether the bearing surface has any irregularities. I might as well replace the bearing. As far as I can see from the posts all it takes is removing rear oil seal cover and pry off a round cast plate.

What do you guys think? Am I finally onto something here? Are there any gotchas replacing the bearing? Thanks for all the help and I hope I can resolve this problem soon.

[hanleyclifford]

Good Work

Looks like you have this problem surrounded. It must have been a slow torturous process as the coupling worked it's way aft out of the inner race and clear of the shaft. By all means do replace the bearing. Everything you need should be available thru the on line catalogue.

[Al Schober]

Good call on finding that crack in the transmission flange. I can see how the flange would receive odd loading if it was carrying torque as it backed off from the tailshaft.
IMHO, replacing the bearing at this point would be good. It's probably OK, but it's tough to say what really might have happened to it during this 'event'. It would certainly be nice to get this beast put back together right the first time.

[Wisakedjack]

I am happy to report that my problem is now fixed. I replaced output coupling, thrust bearing and rear oil seal with the ones from MM. I also put new gaskets and installed shaft nut with washer as suggested in this thread. I did need to tap in new bearing into the housing. New output coupling went in easily by just wiggling a bit in the beginning. I did not need any special tools. I should mention that I did not see any noticeable defects on the old bearing. Before coupling got disconnected we always saw a trickle of oil coming out of the coupling. This has stopped now. Many thanks to everyone on this forum who shared their wisdom and made helpful suggested.