[LEKNIGHT]

bought my boat a month ago. took it out the next day. seemed fine, except for vibration which i thought was just because it was a old boat. also while turning while on throttle it would vibrate more and make noise. i also smelled gear oil.

i drained the stern yesterday and a fast flow of water came out followed by a slow sludge like substance. i was gonna take off the upper gear box to change the bellows. will i be able to see down if anything is really wrong. will new fluid fix the vibration if nothing is really bad in there.

p.s. my stern takes 10W-40 not gear oil

[mtnrat]

Vibration may be from the prop. Is it nicked or bent? As for the sludge definitely change the fluid. Change it a couple of times actually. If the vibration is not the prop, just changing the oil will likely not make much difference, but it sure cannot hurt.

[Don S]

No, new oil will not fix anything, all it does is prevents gears and bearings from destroying themselves.
The ujoints are probably history, along with the bearings and gears in the drive.
Dissassembly and inspection is the only way to know for sure.

[wire2]

Water intrusion means a bad seal. That alone won't cause the vibration, you have a mechanical issue in there also. In fact, the vibration probably took out a seal.

I'd open it up to see, expect to find a damaged gear or bearing. And possibly rust.

[LEKNIGHT]

thanks guys. guess i have some work to do

[Gary H NC]

Once you find the problem and fix it make sure you replace the bellows.Will probably need new ujoints,gimble bearing and new drive shaft.I bet you find the old bellows full of water and oil.