Boater8987

Hey guys, if the drive shaft pinion nut comes loose, can it let the gears move around and cause the bronze looking metal to wear? And are they ruined if some material is ground off ? I am guessing its from rubbing on the shift fork?
I found the drive shaft had no preload and the pinion nut seemed loose. It came off very easy. Thanks Gary

Mr Gadgets

Gary,
what loose pinion bearing preload causes is wear on the case where the inner most bearing rides. It also causes the gear lash to be non consistent. Enough slop and things break.
As far as wear on the brass rings goes. I dont believe the loose pinion would cause that. I would look at your shift linkage. There are two adjustments. One is centering and the other is distance. The second one is adjusted by the merc tool and is preset to allow the shift fork to push the cone into the gear enough that it is forced in by the sprial on the clutch shaft. Then the fork floats. If the linkage is misadjusted so it keeps pressure on the fork against the cone, it will wear. The cam on the fork is what rides on the brass ring, if the distance adjustment it too long it will cause the cam to ride against the brass ring and wear it out.

How much is worn off the brass ring and how deep is the groove in the shift fork? Take a close look at the ramps on the shift fork cams. Threre should only be a tint of brass on the cam. If there is wear on the cams, the assembly should be replaced. The brass rings can be replaced, if your drive is relatively new, but you wont find them from Merc. The older drives, 88-89 maybe had pressed on rings, all the newer ones screw on. If yours are 2002, they are definitely screw on. I take them off used gears, if they are in good shape.
If they are worn too much, you might have shifting problems. I would clean up the groove on the shift fork with a flap wheel, 120grit. Just smooth it out if the goove isnt too deep. Reassemble the drive and and check the linkage and then try it. If you have problems shifting, then it will have to come apart and either replace the rings or the gears.
Also red loctite that pinion nut and have about 5in/lbs of rolling torque. That should do it..

Hope this helps.
Dick

Boater8987

Dick,
Thanks for the great imfo. It gave me a much better understanding of whats going on. I had already purchased a new gear set, because the pinion was starting to shed metal, and installed them today. Along with the updated drive shaft seal assy. and new thrust bearings etc. The shift cam looked good and I cleaned up a slight groove in the shift fork and used red loctite on the pinion nut, with 6in/lb on the preload. I also went thru the lower. I will be working on the other unit tomorrow, it needs a pinion and driveshaft seal. I also heated up the brass ring on the old gear and removed it. Found out it had reverse threads and installed a good used one from another bad gear. Now I have some good used gears and some others I can do the same with. I heated it and screwed the good one on the gear, so it could shrink and be tight. Does it need loctite? I will check the shift adjustment I have the tool. I put 2 new Imco HD transom assy. on the boat last year and I am sure you are right about the shift adjustment, I do not think I checked it. I usually only get 25-30hrs on gear sets and then they start shedding metal with the pinion starting first. The boat gets run over 100+ 80% of the time in poker runs ,playing around,etc.Again, thanks for taking the time to answer my questions.

Gary

Mr Gadgets

Gary,
Are you watching gear lube temps? That long of a run is probably causing heat. My feeling is that cooler oil temps will help the gears.. I also do cryo treating, seeing some extra life there also..

Dick