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.

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 .

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

Canandain built oldsmobiles had 12 bolt chevys. JKaz

12 bolt olds rear
 

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

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.

Yes, but this ring gear has 12 bolts.