OldOldsLover

Hi,
Here's some info I want to share.
A racer Carl i know had some great advice for determining what rear I actually have...contact the pros at...
Quick Performance in Iowa.
515-232-0126
I spoke with Max about identifying what rear I have.
He said there are more than a few rears that went into early to mid 70s oldsmobile.
For the 10 bolt, with bolt in axles, he said to really know if you can get parts you need to verify the following;
1). Count the ring gear bolts on the carrier. There are some rears with 10 bolts covers and 12 bolts on the carrier. You want to see 10 bolts on the carrier.
2). Verify that both carrier bearings are the same size. Some had different sizes. Mark the caps and remove them. Put them next to each other or face to face to look for size differences. You want ones that are the same size.
3). Count the pinion gear splines. Remove the pinion yoke and count the splines. You want 30 splines.

If you don't have 10 bolt carrier, same size carrier bearings and 30 spline pinion...then getting parts maybe next to impossible.
if you do have all of those things then parts are available.
Just looking for housing tabs at 5 and 7pclock, pumpkin webs, etc might no be enough to know what you have.

For me it's nice talking with guys who know their stuff. Sometimes at other online vendors they seem clue less.

Cheers

monzaz

Well that is great... But if they really knew there stuff they would have told you that those rears are not Oldsmobile rears.
The rear with different size carrier bearings is a 8.25 Buick 1968 - 1970 Casting numbers ending in 700 and 724 (you will never find the 2 different size carrier caps in a 2nd gen a body)
The 10 bolt cover and 12 bolt guts is a 8.75 rear that was in the HEAVY DUTY option for towing and big engine cars. They were found in 1973 - 1977 A body
Cutlass (wagons and big cube) and El Camino (car truck) Monte Carlo (454 cube) etc.

Only 2 rears were in the 73-77 A body 10 bolt 8.5 or 8.75 (10 bolt cover with 12 bolt ring) Both and all rears were 30 spline in the Corporate era. (1971 - 1977 ) Full size car and A body car. 7.5 started to come into the works in X body and H body cars.....

All 8.5 in the 73-77 will have the 5 - 7 o'clock triangular castings as picture Chevy or BOP
All 8.5 will have 30 spline pinion yoke spline
All 8.5 will have a 1 1/4" pinion nut OD
All 8.5 will have a casting in upper drilled and tapped brake line hose hold down boss on the top of the casting between the upper control arm bushings.
All 8.5 will have 4 bolt and 2 strap u joint retention

Jim
JD Race

monzaz

You can get gears for ALL gm rears except for
1968-1970 Buick 8.25 (2 different carrier bearing sizes has a GTO / Tempest rear cover)
10 bolt cover 12 bolt ring 8.75 and the 8.875 Full size car Pontiac derived rears (8.75 started in 1971 - ended in 1987 c-clip axles only pinion shaft 1.625) (8.875 Pontiac full size started 1965 - 1976 ended bolt in or c-clip axles pinion shaft 1.875)
Olds 9.3 12 bolt cover 12 bolt ring (1965-1976 1.875 pinion shaft size)
Buick 9 3/8" (1966 -1970 pinion shaft size 1.875 )
1961-1965 Buick drop out pig head rears
1955 and older rears usually

everything else should have gears and parts for.
Even 9 bolt (7.75" ring) Aussie rear in irocs you can get parts for... NOT EASY but you can.
Jim
JD Race

OLDSter Ralph

OldOldsLover......... I should mention that Monzaz (Jim) is our resident rear differential expert. He has done work and supplied parts for many, many people on this site. He knows his stuff !!!!!!

OldOldsLover

Hi monzaz.....
thanks for all the super details
there is just so much info out there
I didn't mean to say that all the items were related to only olds rears, what I was saying that the rears in olds were not only from olds, it might be a buick or pontiac or chevy, im not sure why that is, I think I read there was a union strike or something, but that's not what I was trying to get at. they didn't tell me those were all olds rears, actually the opposite.
when i added this post, it was simply to share the info that I had gotten, so someone who isn't an expert would have some info that might help them.
I think youre light years past me and i will probably never catch up.
I hope i didnt sound like i had all the info or that it was complete.
thanks again for your detailed info.
I appreciate you sharing it.
oldoldslover

i bought a set of motive 4.10 gears and a master rebuild kit from max at quick performance.
Im looking forward to installing them and getting the olds back together, bunch of other things done to it, within the next few months. Can't work in the las vegas summer heat so it's built in motivator
cheers

monzaz

NO - Apologizes...I am just a person like anyone else too. Please do not ever feel that some one is stepping on toes. Were all putting out info...THAT is what the site is all about. Trying to put out the most complete and best info we can. Then if some has more info or conflicting info we have to weed through and make that info more correct. This is how we all will learn ...INCLUDING ME. Especially ME.
Please keep talking and discussing everything.
Jim
JD Race