Changed rear end oil in my 1989 RS last night. I think it might be the first time it was changed since the day it was built. Ive owned the car for the past ten years and have barely driven it during that time. Its pretty much a garage/show queen. I was quite surprised when i crackeed open the rear end and the fluid coming out wasnt black. It still had a gold oil color to it. It was definately low. It looked like less than a quart came out, and it was getting foamy cause there was some foam on the gears. But everything looked good in the rear. So i put it back together and no leaks and put just under 2 quarts back in it. Just wanted to let you guys know that. And this is the first time ive changed rearend lube in a car before and it was quite simple i thought.

 

Only a quart came out, better check for leaks. Pinion oil seal leaking might be the cause of the low fuild. My opinion...

 

Well it looked like it had been leaking but after the fluid got low it hasnt, ill keep an eye on it, but like i said i rarely drive it, only put about 300 miles on it last year. But i will keep an eye on it, i already have the new seal if it happens to be the problem, grabbed one while it was at the parts store.

 

Well its been 3 days or so since i changed the lube. i havent driven it a whole lot since but i have driven it. I keep a peice of newspaper under the rear end after i drive it and its been bone dry since. I did read a thread earlier about someone who ran into the same sort of situation i did. It looked like the pinion seal was leaking and when he changed lube there wasnt a whole lot in it and after he filled it up it stopped leaking. Im thinking something like the heat from not enough lube heating the air, expanding it and pushing the oily air out the seal making a sludge or film that just keeps building up and then starts to drip off the rear somewhere. But the oil is thick enough to seal it. Mine happens to look like it built up on the floorboards on the underside of the car on both sides of the drive shaft. Almost like the U joint area flung it all around. Just some thoughts!

 

Yes, its sounds like a leaking pinion oil seal.

 

Anyone got a repair procedure?

 

Well if i filled it up with new fluid and its not leaking out do i need to replace it? The is not a drip under my car, and i would think that if i filled it up and the seal was bad that it would be coming out, right?

But if i do, I read some older threads and what alot of people have done is measured the distance the yoke is on and make a match mark on the nut and the yoke. remove the nut and yoke pop the old seal out put some lube on the new seal to keep it from burning up, install the new seal, (someone said you can use a chunk of 2 1/2" exhaust pipe). put the yoke back in and install the nut with some red loctite to the match mark and then a flat of the nut further and then double check the distance it is out. Is this ok? Im not hard on this car but i dont want it to take a dump, some people said they have done it this way many times with out problems? Oh, and am i going to loose all my fluid i just put in? Thanks!

 

I wouldn't recomend doing that. If you remove the nut that holds the yoke you will more than likely mess up the preload on the pinion in the diff and potentially damage the rear to the point where you'll have to spend big money rebuilding it. Keep an eye on it and if it isn't leaking don't worry about it

 

Thats what i was thinking, ive put alot of time, patients, and money into this car over the past 10 years to get it where it is now, and i dont want to mess it up myself, i might eventually take it somewhere to have it done but its not leaking out right now and i only drive it maybe once every two weeks, and its only for short distances. Thanks for your help guys.