Pinion seal replacement - The 1947 - Present Chevrolet & GMC Truck Message Board Network

walker · 12-18-2003, 11:52 PM

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 · 12-19-2003, 12:14 AM

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 · 12-19-2003, 12:15 AM

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 · 12-19-2003, 12:16 AM

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 · 12-19-2003, 01:10 AM

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 · 12-19-2003, 01:16 AM

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 · 12-19-2003, 02:20 AM

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 · 12-20-2003, 02:14 AM

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 · 12-20-2003, 02:42 AM

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 · 12-20-2003, 10:40 AM

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.

12-18-2003, 11:52 PM	#1
walker Registered User Join Date: Jul 2003 Location: north of Phx AZ about 30 miles Posts: 698	Pinion seal replacement 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. __________________ Andy,Phx AZ '67 C-10 (Ahhh, done at last. Well there is that disk front end I want to put in and...) "23 C-Cab-sold '48 Ford 8N tractor(still working) '67 Scout(Now on the road) '70 MG B.-sold

12-19-2003, 12:14 AM	#2
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	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. __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

12-19-2003, 12:15 AM	#3
junkyardjohn Registered User Join Date: Aug 2001 Location: SOMERSET KY. Posts: 6,427	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 __________________ junkyardjohn 69 1 TON TOW TRUCK // 84 4WD CUCV BLAZER// 85 1 TON 4WD STAKE TRUCK// 86 M1031 5/4 TON 4WD CUCV// ALOT OF OLD TRUCKS FOR ONE OLD MAN TO DRIVE. THERES ROOM FOR ALL OF GODS CREATURES RIGHT NEXT TO MY MASHED POTATOES// LIFE MEMBER OF P.E.T.A (PEOPLE EATING TASTY ANIMALS) DON'T RENT U-HAUL ALWAYS TELL THE TRUTH IT WILL AMAZE PART OF THE PEOPLE & ASTONISH THE REST

12-19-2003, 12:16 AM	#4
BLACK AND BLUE 67-72 Firefighter Join Date: Feb 2001 Location: Yellville, Ar, USA Posts: 1,943	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!! __________________ '72 Chevy SWB 350 Auto '67 GMC LWB 350 4 speed '70 Chevy 4x4 Stepside 350 Auto Yellville, Ar. USA

12-19-2003, 01:10 AM	#5
OldSkool71 C/10 CLUB MEMBER Join Date: Jul 2003 Location: Lakewood, CA Posts: 993	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... __________________ -Ron-

12-19-2003, 01:16 AM	#6
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	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. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

12-19-2003, 02:20 AM	#7
Tx Firefighter Watch out for your cornhole ! Join Date: Jun 2003 Location: Azle, Texas Posts: 14,162	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. __________________ I'm on the Instagram- @Gearhead_Kevin

12-20-2003, 02:14 AM	#8
jorgensensc Registered User Join Date: Jul 2003 Location: Cypress, Tx Posts: 4,005	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 ? __________________ 1972 C20 Suburban- Big Blue Betty '56 Chevy Bel Air Sedan- Frame up Restoration -What would you attempt to achieve if you knew you could not fail?- -I Refuse To Tiptoe Through Life, Only To Arrive Safely At Death's Door- R.I.P. EAST SIDE LOW LIFE

12-20-2003, 02:42 AM	#9
Rooster's 67 Registered User Join Date: Sep 2003 Location: DFW Posts: 765	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 __________________ The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?

12-20-2003, 10:40 AM	#10
Huck Senior Member Join Date: Jun 2001 Location: Shelbyville, KY Posts: 3,269	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.



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