replacing differential seal -pitfalls??

[m151dave]

I am going to replace the front seal on the rear differential tonight. To be clear, the seal that has the yoke that accepts the drive shaft.

This will be the third time I have replaced a seal on a differential and I have YET to have an install not leak when I am finished. I can only assume that I am doing something very wrong. The only constant appears to be me!

I know I need to sleeve the yoke and I have the part for that as well. But guys, I need to know if there is some sort of trick or secret to this whole seal thing. I can not keep going on this way, I want my diff to stop pissing on my floor!

Any help, advise, warnings would be greatly appreciated!

[rickf]

OK, There are few things I do that I will pass on. First you have to remove the old seal without scoring the surface of the case. Next you have to install the sleeve on the yoke just back from the edge of the yoke. Then I take a fine file and taper the edge of the sleeve so it will not catch the seal and turn the edge over. Now you have to install the seal, coat the outside of the seal with Permatex aviation sealer or a similar sealer. Make SURE you get it started straight and then make sure you install it straight. This is the critical part, take your time. Put some gear oil or grease on the seal surface and on the yoke and install the yoke while turning it and watch the seal to make sure you don't turn the outer lip in. I realize the outer lip is just a dust seal but if it turns it will bend the inner lip and instant leak. It would not hurt to put some RTV sealer or the same sealer as the outside of the seal on the splines also. I prefer RTV for that. Let it sit overnight before filling it and you should be good to go. Even if you scored the case a little the sealer should take care of it.

Rick

[m151dave]

Rick....thanks!! This is great info. We ran out of time tonight, so did not get a chance to do the job, just as well, I had not read your info yet.

I will apply this lesson and report back!

[Crusader_22]

You're the man, rick. I'll be embarking on that one soon. I have a "class 2" leak that I am not quite ready to commit to fixing yet...

Jeff

[svramselaar]

hi

rickf is right to do it

check also the vent assy at the top of the diff if it is open

if not and the oil heated up it will set pressure on the seals

george

[m151dave]

I have never got that far. Bought this rebuilt diff a while back, it sat for over a year before I got around to putting it on the jeep. It leaked at the front seal from the very start. Just sitting there doing nothing the darned thing leaks, a lot.

[m151dave]

The differential in question sat out at the museum and proceeded to mark it's territory by leaking all over the floor! I worried about seals and started this thread.

I needed the vehicle real bad for just a weekend, so I decided to bite the bullet and just fill the diff back up and write off the waste of oil so that the jeep could take part in the show. I trailered it to the event so as not to risk a failure in route. I used a military issue can of oil marked "gear oil 90 weight". The differential has not leaked since. Now the stuff I put in it when I installed the differential originally was 80w90, bought at Autozone. It pissed all over the floor! So what is the big difference in the oils? Is it possible that the 80/90 oil was too thin? Will my new differential with 90 weight in it leak as it warms up and the oil thins a little?