Pinion seal replacement

[walker]

Is replacing the rear pinion seal a pretty straightforward job? It looks like I just need to drop the u-joint, mark the nut, remove the nut, remove the yoke, r+r the seal and reverse the procedure. Does the yoke come off easily? Does the seal come out and go in easily? Is putting the nut back to the same spot the thing to do, or should I measure preload, do the procedure, and reset preload to the same as before?
Just never messed with it before, thanks.

[lukecp]

The yolk comes out pretty easy...mine just slid right off.
The pinion seal will proably come out with a bit of prying around the edges.

Just be sure to get the nut on in EXACTLY the same position. If it is a little off you will slowly destroy your rear.

I got mine on too loose....the pinion came forward and ground up the carrier. I was ill-informed and did not know that it had to be on exaclty as it was before....i know know, lol. So i tightened it down as hard as i could with a 3/4" breaker bar and it seemed OK....that was a year ago and now my rear is shot and i am having to replace it. It could be because the pinion nut is on wrong, but i dunno.

[junkyardjohn]

I REPLACED MINE ON MY BLAZER IN ABOUT 15 MINUTES , START TO FINISH (AND MOST OF THAT WAS DRAGGING OUT & PUTTING AWAY TOOLS) I DIDN'T TORQUE THE PINION NUT (MAYBE I SHOULD HAVE) & JUST TOOK IT OFF & ON WITH AN IMPACT WRENCH. JOHN

[BLACK AND BLUE 67-72]

Yes, count threads and put the nut back in EXACTLY the same place, I would also measure the preload!! I had one replaced and they failed to do this, my rearend did not last two days and it totally wiped out the pinion, it was making a howling sound on the way home and all of a sudden it locked up all most throwing me through the windshield and then broke loose and then it would catch for a second before breaking loose again. When I removed the cover all of the pinion's teeth except three were sheared off!!

[OldSkool71]

Yeah it matters! Mine is leaking too and I can't find anyone to do it. They are afraid and won't guarantee it not to howl. I have to find a rear end guy that knows what he is doing. I don't want to try it cuz I can't afford to replace a rear end right now and shouldn't mine is fine besides a small pinion leak...

[jhow66]

If you measure preload you will have to take the axles out. You would have to measure the preload before you remove the nut so you would know what to put it back to. I replaced the one in my truck 3 years ago (71 Cheyene 502HO) and I just tighten the nut with a braker bar and cheater pipe until tight with no loose motion. Strange timing but I got my brother-in-law's 72 (purchased new-162,000 miles) in basement right now for the same repair.

[Tx Firefighter]

GM procedure they taught us was to mark the nut and get it exactly back the same.

GM felt it was proper enough to do it this way, so I believe in it. Besides, they couldn't afford to pay warranty time on doing it the preload way. That takes a good while and we replaced a TON of 94-98 pinion seals on 1/2 ton trucks (like 1 a day for me).
Only thing I can add, is I have NEVER seen a yoke slide off. Be prepared to whack it several times with a good sized thumper.

[jorgensensc]

I agree with TX Firefighter!!I had to whack the HE!! out of mine with a rubbermallet and I had wedged a hammer handle in through the u-joint sleeves (I tightened them down on the hammer handle) I hit the hammer with the mallet to get it off. It took some persuasion, and slightly bent my hammer handle. Mine still howls, so here is my question:
How do you know if the previous owner did the thread count right? I counted the threads, but it still howls. How do I know if I did it right ?

[Rooster's 67]

Tx Fire fighter is once agian along with many others(I Know he Knows His S#!T, Just look at the sig ASE.) Have proven their knoweledge

Technicaly the only way to do this the right way is to remove the axles and measure the preload on the pinion and take back lash readings(taken at the ring gear), remove the nut which may require a big impact or cheater bar, remove the yolk, remove the seal. remove the outer pinion bearing, REMOVE THE CRUSH SLEEVE, replace the crush sleeve, replace the front pinion bearing, replace the seal, replace the yolk, tighten said nut to the specified(or previously determined back lash and preload)preload.

That is the proper way to do it!

But,

Every now and the EVEN a blind Squirrell will get a NUT!!!

And tightening that SOB will Require a lot of A$$ to tighten, or a big cheater pipe

[Huck]

This may be uguly but----this is the one really weak area in the design of our trucks---the rear. FORD had a better idea especially with their 9" quick change rear. Sorry but it's true!!
My 72 had a leak, did the marking of the nut etc.---still it got noisey after the change. Did an upgarde to a posi---had an excellent mechanic to the set up---but---the damage had been done.
I would suggest bringing the truck to a rear end speciality shop that will change the seal and redo the set up guaranteeing their work. Might just invest in a posi or gear upgrade at the same time.