12 BOLT OLDS REAREND WITH 12 BOLTS ON RING GEAR...HELP!!!!!!

[gungho]

I have an olds 12 bolt rearend but it has 12 bolts on the ring gear not ten like it is supposed to please any info wil be a big help,thanks Bryan

[Tod74]

I have seen the oposite...I got took once when I was in High school cause I bought a rearend thinking it was a 12 bolt cause there was 12 bolts in the cover....but it only had 10 in the ring gear. I learned later that some Olds rearends were like this.

If you have one with 12 in the carier that is a better rear end than the 10.

[gungho]

I was told all oldsmobile rears had 12 bolts in the cover with 10 on the ring gear,I cant find anything like it anywhere,has anyone? the posi carrier has a 700 cast in it and it has "S" springs holding the cluthes in place noe like chevys regular spring

[Tod74]

I was told all oldsmobile rears had 12 bolts in the cover with 10 on the ring gear,I cant find anything like it anywhere,has anyone? the posi carrier has a 700 cast in it and it has "S" springs holding the cluthes in place noe like chevys regular spring

That is exactly how mine looked...but it only had 10 bolts in the carier and 12 in the cover. Just measure the ring gear that will tell you which one you have for sure.

[cepx111]

Now I dont know about BOP rearends but I have always thought that when a rearend was refered to as a 10 bolt or 12 bolt, it was in reference to the cover bolt count, not the ring gear bolts.
Tod is exactly right, always measure the ring gear itself and then you'll know for sure what you have.
Heres a link to a olds only site on their rearends.

http://www.oldsmobility.com/10bolt-tech.htm

Goodluck, Charles

[Tod74]

Now I dont know about BOP rearends but I have always thought that when a rearend was refered to as a 10 bolt or 12 bolt, it was in reference to the cover bolt count, not the ring gear bolts.
Tod is exactly right, always measure the ring gear itself and then you'll know for sure what you have.
Heres a link to a olds only site on their rearends.

http://www.oldsmobility.com/10bolt-tech.htm

Goodluck, Charles

No...it refers to the ring gear bolts...but they normally coincide with each other...That is what I thought back when I bought that one(cover bolts)...but that goof ball olds rearend I had had 12 bolts in the cover, 10 in the ring gear and the axles from a 10 bolt fit it, but the ones from a 12 didn't....best I remember that was 20 years ago...was given the bad news by the guy I hired to build the rearend for me.

[gungho]

I know what I have i have a 12 bolt olds rear,12 bolts on the cover and 12 on the ring gear .what is measuring the ring gear gonna tell me??is there more than one real 12 bolt olds rear??Im looking to see if anyone can tell me what this is,I was told olds didnt make a real 12 bolt and I cant find one like it anywhere, thanks for any help guys.

[mytmouz]

Does it have c-clips or do the axles bolt in similar to a 9 inch ford?

[gungho]

no c-clips it is retained out at the drums,and is a car because it has the ears cast in it for the control arms is about 57.5 from backing to backing

[Tod74]

http://www.classicoldsmobile.com/tech/73.shtml

http://www.oldsmobility.com/10bolt-tech.htm

Measuring the ring gear will tell you which carier you have..that's what it will tell you.

A "real" 12 bolt as you called it, had an 8.875" ring gear.

http://www.drivetrain.com/gm8.875car.html

[gungho]

where have you seen a olds 12 bolt ring gear rearend?this is not a chevy 12 bolt I have 2 chevy 12 bolts here,and it is nothing like it,my question is has anyone seen this or have any pics or know the application I bought it to put under my 72 chevelle but found out the chevy diff cover dont fit

[Tod74]

where have you seen a olds 12 bolt ring gear rearend?this is not a chevy 12 bolt I have 2 chevy 12 bolts here,and it is nothing like it,my question is has anyone seen this or have any pics or know the application I bought it to put under my 72 chevelle but found out the chevy diff cover dont fit

MEASURE THE RING GEAR ..then it will be easier to find out what it came out of.

[mytmouz]

Sounds like a Dana 44, but the cover on those for the BOP's is usually a 10 bolt...

[Tod74]

Sounds like a Dana 44, but the cover on those for the BOP's is usually a 10 bolt...

they had them with 12 bolts too but the cover is smooth and round like a 10 bolt .

[JEFF69Z28]

12 BOLT IS HOW MANY RING BOLTS THE RING GEAR HAS NOT SO MUCH HOW MANY COVER BOLTS.

[kaz442]

Canandain built oldsmobiles had 12 bolt chevys. JKaz

[monzaz]

You have a full size 12 bolt olds rear diff. 1967-1970ish deltas 88 98 had a 12 bolt FULL size 'O' type 12 bolt rear. This rear came with 12 bolt symmetrical cover and 12 bolt ring gear .

The 12 bolt mid size or A-body GM 'O' 12 bolt with a symmetrical cover has 12 bolts on the cover and 10 bolts on the ring gear. These were in the olds cutlas, 442 AMERICAN made cars only 1967 -1970. Canadian car received the 12 bolt chevy rear and was open non posi diff.

then in 1971 1972 the rear was a 10 bolt 8.5 corperate just like the all the 70's and 80's cars and 1/2 ton trucks...ONLY they came wioth bolt in axles.

1973 was the switch to a new body style so that rear will not bolt into the 1972 and older body style.

So I am sure you have a FULL size 12 bolt 'O' type rear in your hands there. If I had pictures of the housing cover and or posi unit I could ID it for sure. Jim

[gungho]

http://img257.imageshack.us/img257/3959/dsc02269hh0.jpg

[Tod74]

That is the exact same rearend I had that I mentioned previously...right down to the "S" spring in the carier. mine had 10 bolts in the ring gear and the axles from a 12 bolt chevy did not fit.

[gungho]

Yes, but this ring gear has 12 bolts.

[purestock20c]

Not to confuse you any more but i had a 76 lemans that had this same rearend from the factory 12 bolt cover 12 bolt ring gear. Measured 8 7/8 but a standard g.m. 12 bolt ring gear would not match up. All i found out is that gm had alot of odd and end parts they put in their cars in the 70's. If you are not drag racing throw it out and put a weak 10 bolt 8.5 under it.