1991 Chevy Caprice Differential

[WyrTwister]

Inherited the car from Mom and Dad . Has set many years . Have driven it a little , off and on , the last few years . Currently it is parked .

Pinion seal started leaking on it . I am guessing , dried out due to not driving it . Car has ~ 46,000 actual miles on it .

I changed the seal . Car has a whine , when decelerating . Does that mean , I need to tighten the pinion nut a little more ?

What is the pre-load suppose to be , old gears , bearings and wheel seals . I have a new style diff cover seal that I plan to use & change to a thicker lube .

Thanks ,

 

[Astro14]

It's been a long time since I've done a GM pinion seal, but I recall some of them having a non-reusable crush sleeve that set the pinion bearing pre-load...

Was this one of those?

Or is a torque value that sets pre-load?

Either way, it was quiet before, so your work is what changed it, and I suspect, as you do, that the pre-load is off...and I suspect that this is similar to the 10 bolt on my old Trans-Am that needed a new crush sleeve when doing the seal...

 

[ragtoplvr]

Has crush sleeve. You should have left it alone. You have to mark the nut before you remove it. You willl have to have a sleeve now, that is a pain in the [censored].

Best course with something like that is to use some motor leak stop in the diff oil.

Rod

 

[dlundblad]

Not sure what diff this has, but I replaced the 7.625's pinion seal on my truck last summer. I made a mark on the nut to the housing prior to removal and reinstalled at the same position. ~5k or so with no issues.

You could start by making certain the yoke bolts are torqued correctly.

 

[DuckRyder]

Originally Posted by ragtoplvr
...You have to mark the nut before you remove it. ...


Yep, and if you've run it very much it is probably toast.

 

[Trav]

Loosen the pinion nut but do not remove yet, remove the axles and ring carrier. Now remove the pinion nut while holding it in the housing, yoke and crush sleeve, you will not need to measure for spacers as it was a good running unit but you need a new crush sleeve.
Install the sleeve, seal (grease the seal lip), yoke and nut, use a tool (make one or buy one) to hold the yoke. Tighten the nut until you feel the sleeve contact the pinion, do this in steps a little at a time, its going to get tight as the sleeve begins to crush. If you go too far you need another crush sleeve then use a low inch pound torque wrench with a scale and tighten till you get 10-25 lb-in preload.
That's it, reinstall the carrier and axles.

This will do it..

https://www.amazon.com/Neiko-03727A...mp;psc=1&refRID=QM9FZNAR7HY9TBEQX6JV

https://www.amazon.com/Allstar-Performance-ALL68372-Pinion-Wrench/dp/B004QGBMT2

Edit: I got the preload spec from an old book for a GM 10 bolt. Please confirm with either the FSM or a dealer mechanic.

 

[clinebarger]

Originally Posted by Astro14
It's been a long time since I've done a GM pinion seal, but I recall some of them having a non-reusable crush sleeve that set the pinion bearing pre-load...

Was this one of those?

Or is a torque value that sets pre-load?

Either way, it was quiet before, so your work is what changed it, and I suspect, as you do, that the pre-load is off...and I suspect that this is similar to the 10 bolt on my old Trans-Am that needed a new crush sleeve when doing the seal...


The crush sleeve "can" be reusable, It all depends on IF it rebounds when preload is removed via loosening the pinion nut. If you get slack in the pinion bearings right away when loosening the pinion nut.....The crush sleeve is rebounding & still good enough to return to service.
If the light press on the front bearing & the sealant on the Yoke splines is enough to keep preload on the pinion bearings....The crush sleeve is DONE.

I don't like using crush sleeves at all, Just about EVERY GM corporate differential can be converted to a solid spacer....Then you use shims to set final pinion bearing preload.

GM used generic no-name bearings in a lot of differentials starting in the late 1980's into the nineties, Before that GM used a mix of Hyatt & Timken bearings which were very high quality. Warranty work went through the roof during this generic bearing phase, Then they started using Timken & Koyo with far better results.

If this differential is whining.....The pinion bearings are probably toast!

 

[Gasbuggy]

I would undo the driveshaft and see how much slack is in the diff. If it's tight, loosen it a bit and see if it's quite.

 

[Lubener]

Originally Posted by Gasbuggy
I would undo the driveshaft and see how much slack is in the diff. If it's tight, loosen it a bit and see if it's quite.


Won't matter once the crush sleeve has been over torqued. Disassembly is likely in order. Unless it was a major leak, I just would have topped up the lube once a year if that.

 

[Trav]

Originally Posted by clinebarger
Originally Posted by Astro14
It's been a long time since I've done a GM pinion seal, but I recall some of them having a non-reusable crush sleeve that set the pinion bearing pre-load...

Was this one of those?

Or is a torque value that sets pre-load?

Either way, it was quiet before, so your work is what changed it, and I suspect, as you do, that the pre-load is off...and I suspect that this is similar to the 10 bolt on my old Trans-Am that needed a new crush sleeve when doing the seal...


The crush sleeve "can" be reusable, It all depends on IF it rebounds when preload is removed via loosening the pinion nut. If you get slack in the pinion bearings right away when loosening the pinion nut.....The crush sleeve is rebounding & still good enough to return to service.
If the light press on the front bearing & the sealant on the Yoke splines is enough to keep preload on the pinion bearings....The crush sleeve is DONE.

I don't like using crush sleeves at all, Just about EVERY GM corporate differential can be converted to a solid spacer....Then you use shims to set final pinion bearing preload.

GM used generic no-name bearings in a lot of differentials starting in the late 1980's into the nineties, Before that GM used a mix of Hyatt & Timken bearings which were very high quality. Warranty work went through the roof during this generic bearing phase, Then they started using Timken & Koyo with far better results.

If this differential is whining.....The pinion bearings are probably toast!




Yes, I forgot to list that in my post "check the bearings" if he drove it around they are probably damaged but its no big deal to swap them if the carrier is out.
I am interested in this spacer and shim, is there a kit for this? This will work with late model diffs found in pickups? I haven't worked on GM diffs at the dealer level since the early 80's so I missed the generic bearing failures it seems.

 

[MarkM66]

Originally Posted by Trav
Originally Posted by clinebarger
Originally Posted by Astro14
It's been a long time since I've done a GM pinion seal, but I recall some of them having a non-reusable crush sleeve that set the pinion bearing pre-load...

Was this one of those?

Or is a torque value that sets pre-load?

Either way, it was quiet before, so your work is what changed it, and I suspect, as you do, that the pre-load is off...and I suspect that this is similar to the 10 bolt on my old Trans-Am that needed a new crush sleeve when doing the seal...


The crush sleeve "can" be reusable, It all depends on IF it rebounds when preload is removed via loosening the pinion nut. If you get slack in the pinion bearings right away when loosening the pinion nut.....The crush sleeve is rebounding & still good enough to return to service.
If the light press on the front bearing & the sealant on the Yoke splines is enough to keep preload on the pinion bearings....The crush sleeve is DONE.

I don't like using crush sleeves at all, Just about EVERY GM corporate differential can be converted to a solid spacer....Then you use shims to set final pinion bearing preload.

GM used generic no-name bearings in a lot of differentials starting in the late 1980's into the nineties, Before that GM used a mix of Hyatt & Timken bearings which were very high quality. Warranty work went through the roof during this generic bearing phase, Then they started using Timken & Koyo with far better results.

If this differential is whining.....The pinion bearings are probably toast!




Yes, I forgot to list that in my post "check the bearings" if he drove it around they are probably damaged but its no big deal to swap them if the carrier is out.
I am interested in this spacer and shim, is there a kit for this? This will work with late model diffs found in pickups? I haven't worked on GM diffs at the dealer level since the early 80's so I missed the generic bearing failures it seems.


Think it's something like this

https://www.quickperformance.com/GM...n-Spacer-Adjustable-w-shims_p_21511.html

 

[Trav]

Thanks for that. That looks like what I had in mind.

 

[Astro14]

Sea story about a crush sleeve:

In about 1992, I had my 1985 Trans-Am in for a set of tires. 4 new Goodyear Eagles.

The shop in Virginia Beach pointed out that the pinion seal was leaking and they recommended changing the seal. I was leaving on a road trip the next day, and didn't want to fuss with it, so I had them do it. Cost about $65, parts + labor.

As I headed up the Eastern Shore of Maryland the next morning, a Friday, the rear end started to howl. I ended up near Wilmington, DE when it got loud, and I had to stop the road trip. 200 miles from home, I had few options. Via the Yellow pages (ah, yes, those days) and a pay phone, with lots of quarters, I found a local shop that was open and able to do the work on a Saturday. They rebuilt the rear end the next day (10" GM) with all new bearings and seals. Cost a bit over $400, parts + labor. They were kind (I think the leather flight jacket as an ice breaker helped, and they really were helpful in getting me back on my road trip).

I couldn't prove that the Goodyear store in Virginia had failed to set the pre-load correctly, but I know that's what happened. I mean, it was obvious. They charged me for just a seal in the parts list, but NOT for a new crush sleeve. I talked with my attorney (a fellow navy pilot had a brother who was an attorney, and he had done some legal work for me previously), about my options and it, honestly, was too expensive to take the Goodyear guys to court, given the uncertainty of winning.

A few weeks later, back from the trip, I walked back into the Goodyear store, spoke with the manager, showed him my receipt/work order from his shop, and the receipts/work order for the work done 200 miles later and asked that he pay for the whole thing. All $400. He denied any responsibility, of course, and was pretty hostile, but I did manage to get them to refund the $65 they charged for the seal replacement, since, of course, the seal was leaking 200 miles later when the pinion bearing had given up the ghost. That much I could prove, and in court. I told him that.

As he and I walked out of his "office" he loudly proclaimed to the other employee that I was to get a refund of the $65, and that "This guy (meaning me) is banned from my shop! I don't ever want to see him in here again!". A real jerk.

Ah, the days before social media, and internet, when I would've taken this story, including pictures of receipts to every review site, every social media forum.

I did file a complaint with the BBB, including copies of receipts, and a copy of the page from the factory service manual showing the requirement for a new crush sleeve to set the preload, and Kramer Tire corporate later contacted me with an apology for the "banning" and an offer of 10% off any service or tires in the future. A nice, but insufficient, gesture. I did happen to mention my story to every single person that I ever talked with about cars, and strongly recommended that they avoid Kramer Goodyear on Holland Road, in Virginia Beach.

That shop closed a few years later.

Wonder why...

 

[Trav]

That sounds like horror trip. They don't get top shelf mechanics in those type of places that's for sure, they pay peanuts and that's what they get.

 

[Astro14]

Originally Posted by Trav
That sounds like horror trip. They don't get top shelf mechanics in those type of places that's for sure, they pay peanuts and that's what they get.


Yeah, I lost a day, and $400, which was a lot of money for me at that time.

One of many times that I've regretted having a "shop" do work on my cars.

That car had water in the oil a few years earlier. I did the head gaskets myself, and I had the FSM (a big paper book) as well as the lifts, and full set of tools at the Oceana Auto Hobby Shop, so a pinion seal was well within my capability.

I was trying to save time and worry before a road trip.

Ended up losing both.

 

[WyrTwister]

( Has not been driven very far since the seal replacement . )

I have been told that , if I failed to tighten the pinion nut enough , it would whine or howl on deceleration . Which it is .

And howl or whine on acceleration if too tight . Is that true ?

If true , back to the original question . What abought tightening it a little more ? The crush sleeve should not be over crushed ? Should not need replacing ?

Second part of my original question . What should the correct torque be , used internals , to give the correct pre-load ?

 

[ragtoplvr]

You will have to have a 100 inch pound torque wrench beam or dial, not electronic unless has continuous readout. And some way to adapt to the pinion nut. Then you take off the driveshaft, wheels, tires and brake drums or lift rear calipers out of the way. No extra drag.

Then you adjust for a rotating torque of 10 to 25 in lbs . If nothing was damaged it should become quiet.

If not then that rear end should be plentiful in the wrecking yards. or prepare to replace crush sleeve after checking the bearings.

Rod

 

[Trav]

The carrier and axles must be removed to attain correct preload numbers.

 

[nthach]

Originally Posted by Astro14

That shop closed a few years later.

Wonder why...

TBH, I've never liked Goodyear dealers/stores. Always had a bad experience at them mostly. There's one near my parent's place that can do decent work but the pricing and customer service is bleh. The one near my apartment changed names and they're hacks.

 

[clinebarger]

Originally Posted by Trav

I am interested in this spacer and shim, is there a kit for this? This will work with late model diffs found in pickups?


Ratech & Yukon make solid spacer kits for the 8.5" that also work on the 8.6"......The last time I checked no one made a kit for the 9.5" 14-Bolt semi float, For the few performance 9.5" I've built, I machined a chromoly spacer on the lathe.