AZ455

8.875" P - 10 bolt cover/12 bolt carrier

I just wanted to make a thread to gather any information possible about this rear end. It seems almost impossible to find anything for, even gaskets.

Anyone know a source for parts for these? Cover gasket, pinion seal, etc?

I guess this is the Olds/Pontiac axle used in some full size GM cars for a few years. However, it seems like nobody makes parts for them? I did finally find a cover gasket by Fel-Pro (RDS 30031) that appears to be correct by the shape. Just trying to gather resources if anyone knows about these uncommon diffs.

AZ455

O'Reilly auto parts shows that the same pinion seal is used for the 8.5 and this 8.875, not sure if that is correct or not.

copper128

Jim at JDRace.com (monzaz here on CO) can get you the parts you need for that axle.

monzaz

Yes there are rebuild parts

The pinion seal is the same as a 8.5 2043 on all except for the 1965 year...WHY? who knows...lol. 65 seal is the samer as the drop out Pontiac Olds seal in the previous year. lol. Silly.

Rear cover gaskets are a ORDER ONLY part in the o'rileys and maybe other stores.

Bearings are pretty easy to located also

carrier bearings are basically 12 bolt chevy carrier bearings
Pinion bearing is the same as a 489 mopar
outer pinion bearing is the same as a 12 bolt chevy and 8.5 chevy again

In 1971 1977 a-body the 10 /12 bolt rear changed inner pinion bearing size to 1.625 same as 12 bolt chevy bearing. This rear was used in the mid size a-body as a upgrade performance option el camino, olds cutlass, 454 Monte Carlo, etc.
1971-1976 Full size kept the same large 1.875 shaft size

1965-1970 3.55 gears are available from Fab Craft metal works i can also get them for you if you need. You will need a 8.5 yoke as the gears are made with the 30 spline pinion shaft not the old 28 spline. 1971-1977 had the 30 spline pinion shaft option (bigger is better in this case. )

You can get all these part numbers from www.jdrace.com web site too. just look in the I D Differential key left of home page.

Hope this info has help and NOT CONFUSED.... Jim

JD

AZ455

Not at all, that is exactly the information I was looking for. Thank you!

I don't need any parts immediately, but I saved your site for future use. I am hoping I can swing some new gears sooner than later...

olds1966

Hi,
I am using this differential mine has a 2.56 gear set. This post is first I have heard that a gear change is possible. This is exciting news. If using a 1965-1970 gears and a 8.5 yoke, would it also be possible to use a aftermarket posi carrier of some sort?

GEARMAN69

See FABCRAFT on EBAY they sell a 3.55 gear set and new differentials , there are there gear series and 2.56 is series 1. The 71-76 Pont cars are also 8.878" 10/20 but use a a yoke spline different than 65-70 same otherwise. , the 2043 seal interchange doesn't mean use a 8.5 yoke. Donor cars like 69-70 Bonneville with a 2.93 or 3.08 Safe t Track are out there too sometimes a a 3.23 Safe track comes up 3.42 is rare 2.73 Safe T Track in Grand Prix automatic too or any manual shift car with a Safe T Track tag gets a 3.23+ 65-76 donor opportunities plus FABCRAFT

monzaz

FABCRAFT has not had 3.55 gears in over 7 years now...doubt will ever see them again...same with buick 8.2 68-70 special gears i help make happen years ago.
Brad sold the company and it has really not been the same since.
No equity to make the gears so...i really do not see it happening unless some over there hit the lotto.
I tried to tell them to sell the right to one or 2 of the gear sets to like a Randys ring and pinion for a big chunk of money so they can build other gear sets they need.
Example:
sell off the 8.2 Buick special 68 -70 gear sets rights....
then they would have money to make the 3.55 Pontiac 8.875 gears..??
I do not know. I pretty much canned building and buying anymore cores of the pontiac full size car rears if i can not get the parts. It is sad.

Jim
JD RAce

olds1966

Thank you guys for all information. Not what I was hoping for but at least I know now to look for another differential or deal with really tall gears. Any thoughts on what would be easiest / best swap.

monzaz

That is the problem....No Easy swap.
Jim

joe_padavano

The 1965-70 Olds full size cars use unique frames, suspension, and brakes as compared to other B-body cars. Nothing else swaps. Impala parts do not fit.

GEARMAN69

Yeah I thought I had seen the FABCRAFT stuff on Ebay from the new owners but then looked it up after I posted and it was not there anymore , I thought I had seen the new differentials available not long ago.. but yeah I grab any of the good used OEM stuff when I can and hold on to it for me and my buddy have a couple 65-66 cars, he still has a 67 3.42 Safe Track set up from a rare stick shift 2+2 that ended up being parted , been building up stock here on 57-64 9.3 stuff too for spare on my 63 Cat and order future old school builds .. I have been lucky to score some good gentle used hard to find units for my cars.. a cream puff 65 Olds 2.78 Anti Spin rear donor rear to build our 69 Firebird 400 back to a nice set 2.78 and series 1 Safe t Track in the original 2.78 open housing that had gotten rusted and a another low mileage Unit Series 1 BOP safe t track unit to go on our cream puff 2.56 gear 69 Lemans but its was off a 71-72 with the bigger 7/16LH ring gear bolts and I found Yukon had tiny sleeves I bought to put the 3/8 RH ring bolts thru