What can be causing my rear end to leak?

Venom351R

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Apr 27, 2002
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The car has been sitting in the same spot in the garage and not driven since March. It was last moved just before that on a flat bed from the previous garage to where it is now. Before it was moved there was no leak but now there is. It appears to be leaking where the drive shaft connects to the rear end, its not coming from the cover but appears to be right where the yoke is at the rear end.
 
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That would be the pinion seal most likely, its a seal right behind the yoke.... maybe it dried out some from not being used??? kinda odd as they usually never have a problem.
 
If it was sitting in the first instance for a long time I can envision where the pinion seal may have dried out and the moving of the car last March caused the seal to tear if it was stuck to the pinion shaft.
 
It's your pinion seal. Usually it leaks after a gear change. Mine's been leaking since the dawn of time, but I'm too lazy to change it, so I just keep topping off the pumpkin.

Kurt
 
I want mine fixed I hate leaks. On another forum I was told to remove the ring and pinion gear and to get a new crush collar, but my haynes manual says just to remove the drive shaft, take the seal out and put a new seal back in??
 
You have to remove the mount plate for the driveshaft, which means you have to take the big nut off the pinion gear. You really should put a new crushwasher in. While you have it out, take some medium sand paper and sand the surface where the seal rides. That will ensure a good break in.

Kurt
 
If the bearing is ok, then you probably won't have to. It depends how tight it is all in there. Usually, you pull the whole carrier out, and then have to hammer the pinion loose from the flange there. As long as you keep all the shims in the right place, and put it back together the exact way it came apart, then you shouldn't have to remeasure for shims. It's one of those pain in the butt jobs. That's why mine still leaks.

Kurt
 
IIRC and you don't want to replace the crushwasher, then before you remove the nut check to see what it is torqued to and then torque it to the same amount when putting the nut back on. That should leave the pinion gear in the same relative position as when you started.
 
Ok from what I have seen from video's online and my manual it says to check the preload of the nut with a beam style inch TQ wrench. As far as the process it seems straight forward, Remove the driveshaft, mark everything so it is all lined up the same. Use a puller to pull the flange off then check the pre load of the nut and remove it. Pull the seal out w/ a puller, clean up the whole area with some brake cleaner and install the new seal with some grease. As far as putting the seal back in Ive seen 3 ways of doing it. One is w/ a seal installer which I can find online but for a price of $90 which I dont want to spend on a one time repair. The other way I saw was that someone used a 2X4 piece of wood and pressed it up against the seal and differential and pounded the seal in that way, and the other way I read about was by using a large socket which to me seems the best and most inexpensive way if only needing to by the right size socket VS using the 2X4 method.

Now I dont have a beam style inch TQ Wrench so that would be another expense for a one time or not worth it for the amount of times use. So what I also saw is that if you mark the pinion nut and count the # of turns it takes to take it off according to the mark you placed on it and put it back on the same amount of turns your preload should be the same correct?
 
The preload needs to be done with the dif out....you need to get that preload with it turning freely....if the pinion gear is in the ring gear your reading is bogus as your turning the entire dif assy...

How bad a leak is it???
 
From all the articles I've read online and the Haynes manual it says to check the preload without having to remove anything. The leak is bad enough to warrant replacement.

I guess Im confused on exactly how to check the preload. I have two different sources saying either to take out the whole differential or it can be done with it all in. The Haynes manual says to replace the pinion seal and with checking the preload with the differential assembled. The only thing that needs to be taken off/out of the car is the driveshaft and the flange at the front of the differential, then remove the nut take out the old seal, place in the new seal and reverse the order to reinstall everything.


What seemed really simple at first is now getting really confusing. Does the pinion nut have a TQ specification??? Or is it just placed onto the pinion gear and tightened down and then the rear end is spun using the inch lb torque wrench until the reading is seen that was recorded before it was all taken apart?? And if that is correct how do you do that with a click style inch lb torque wrench instead of the beam style which has the needle indicator for how much force is being applied??
 
Anytime Ive done a pinion seal the dif was out...hence my response... but that write-up would work just fine....take time & doublecheck yourself creeping up on the preload.....:nice:
 
ok so I got everything that I needed to do this and I just went to measure the amount of preload on the rear end before taking off the nut and the pinion seal. From what I have read online the preload should be between 15-25 inch lbs but I am getting a reading of only a few inch lbs the needle is barley moving on the lnch lb torque wrench. I read as well that if the brakes are dragging it could be an issue so I removed the calipers so the axle spins freely with nothing hindering it. But like I said its barley showing any preload at all???