g741.org

Hello All,
I serviced both differentials this past week and filled them both with a Synthetic 75w90 gear oil, which I believe I had read on this site that is what I should use. However, since servicing the differentials, both the seals where the u-joint shaft enters are now leaking. Did I choose the wrong gear oil or because it is new and clean caused the seals to start leaking... any thoughts?
Thanks,
Dennis

What seals did you use? Did you use a ready sleeve(if necessary)? There are basicly two things that lend to leaks, bad sealing surface on the yoke, or bad seal- you should be using new design seals, not the old leather ones.

What Bob says. I just went through this with the rear differential on my truck. A new neoprene seal with a sleeve on the yoke fixed it right up.
There is also information on this site about using the outer shell from the leather seal, and replacing the inner portion with a modern viton seal. While this should in theory work, I couldn’t get it to seal properly and went with a new rubber style seal instead.

Synthetic oil will find the magic way out of any device...

The tradeoff is things won't wear out in your lifetime.

I keep my stuff clean with 50/50 mix of Diesel fuel and dish soap. Spray it on, wait a bit, rinse off with a hose. Voila!

PoW

Thanks gentlemen, as always I appreciate the wisdom...

So, considering that Fiona sat for almost twenty years, I guess I should replace the seals! Duh!! They weren't leaking prior to the servicing, but that could be because the fluid was a gel... LOL!! Thanks for the photos for the new seals I need to purchase.
Thanks again!
Dennis

Can someone post the part numbers for a new seal & sleeve ?

Are you sure it is leaking from the seal? Gear oil can make its way along the yoke splines and leak. I put sealant on the spines before I push the yoke/flange on and tighten the nut.

I didn't even consider the yoke splines... thanks for that. I'll clean everything up and double check before proceeding.
Dennis

Good Afternoon gentlemen,
After close examination, I have found that the gear oil is definitely leaking past the yoke splines. Any recommendations as to how I might fix this?
Thanks,
Dennis

Some folks pack a good thick sealer inside the female end then mate then up, reinstall it then letting it set up. Some also add a gasket and sealer under then flange nut washer.
Gary

Any recommendations as to how I might fix this?

I have started using - The Right Stuff - https://www.permatex.com/products/gaske ... ket-maker/

Pull off the yoke/flange, clean the gear oil off as best you can, put the sealer on the pinion slots and in the yoke/flange. Then reassemble.