Boat is a 1988 Formula 311 with TRS drives and 420hp motors. Engine mounts are offshore and they are front and back plus the tranny mount.

I was idling in from the lake the other day and I heard a horrendous noise. When I put the boat in neutral the noise went away. Reverse and the noise was back. Drive trim or turning did not seem to make any difference. I pulled the boat out of the water and if I turned the prop by hand there was a clunk. So I pulled the drive and checked my universals and also the gimbal bearing. Everything seems OK. I took a spare drive shaft and put it into the tranny and spun it and it was smooth as can be. I did notice that the tail shaft of the tranny is not even close to being centered in the transom assembly. It is way out of allignment. I would say it is almost an 3/4 of an inch off. So we were thinking that the stringers must be rotten. Everything is OK after I pulled the manifolds and gave it the tap test. No indication of crushing stringers or anything. No indication that anything has moved. So now I am wondering if this has always been this way and what I should do??????

Thanks
Jon

I just tested the alignment and it is ok. I assumed it was bad by the looks of it but everything slid in fine. The drive came off fine as well. So now I am totally at a loss.

is the noise still there? I mean can you run it without the drive? I had reverse squealing once in the tranny.

I assume the noise would be there if I put the drive back on. I am going to test that tomorrow. I am also going to pull the drain plug and see if the fluid is clean, maybe something went in the drive?

Either a upper gear or a lower gear came apart!! Chances are u didnt feel it a wot but it def. found it at idle.. had the same prob.. Good luck.. Thats why im going to Bravo

Would I not feel it when I am turning the drive over by hand?

Should be able to run that with the drive off. Assume with that being a '88 you have Borg-Warners.

Where the trans tailstock slides into the transom assembly there is a shoulder made around the bottom half of the hole to the rear. I believe this shoulder was originally intended for the Merc Trans ll transmission tailstock to seat against. However viewing the trans tailstock from outside the boat by looking through the bellows this shoulder around the bottom half makes it appear as if the tailstock is off center though it really isn't.

I would pull the upper cap off and look at the upper gears. I had one break and although it turned freely by hand, under load the gears would slip and clunk

I will do that this evening.....

just had similar problem with my trs drive ended up being a chipped pinion gear in the lower still felt smooth by hand even with a tooth missing