help ID a GM rear

I aquired a GM rear end today, dont have any pics yet, but I was wondering if you could help by telling me what it is and what its out of. Not real familiar with old GM diffs. Its about 52 backing plate to backing plate, the chunk or pumpkin is installed from the front similar to 8 or 9 inch. Its an older diff...I can see that it has a "GM" and series of numbers that I could not make out, need to clean and see.

I will get some pics and numbers, but just wondering if you could tell me possibly what this is out of?

thanks,
Mike K.

 

Is the banjo round or square when viewed from the back? What are the numbers marked on the pumpkin? No tags? Is the diff set up for leaf springs or trailing arm suspension.
Squirrel can probably help with this, he knows his Chevys...

Flatman

 

Pics or a more complete description would be a big help! In general...if the pumpkin is kind of flat on the top and bottom, it's probably 55-64 chevy. If it's round, and the rear cover also unbolts, then it's probably 55-62 pickup. If the pumpkin is round and the rear cover does not unbolt, probably olds/pontiac.

 

Alright, I tore into it...its in great shape, 3.36 gears ...54" backing plate to backing plate and numbers casted on the pumpkin are 3725899 GM15
trailing arm setup...so my guess is its 58 or later, right? It has pretty large breaks on it, was thinking it was a truck. Its not posi, and only the front, pumpkin comes out, no removeable rear cover.

What do you think? Sorry, I dont have any pics yet, digital camera is not here.

thanks in advance, any sites or info will help.

 

is the pumkin round or oval? round is poncho/olds, oval is Chevy car. GM trucks were 6 lug thru 1970....and 62 was about the end of the drop out third members.

Chevy cars had trailing arms starting in 58, the 58 upper arm was centered, 59-64 were off to one side.

Should also be a casting date code on it.

 

If it's got 3.36 gears, it should be a Chevy rear. To my knowledge, the Olds/Pontiac rears never ran that ratio; they went from 3.23 to 3.42.

 

God, I cant remember for the life of me if its round or oval. It has an off center upper trailing arm...and its 5 lug.

 

Its definatly 3.36 37 ring and 11 pinion

 

59-64 Chevrolet passenger car has a single upper trailing arm and 11 inch brakes.

 

I think thats what I got folks....now any resources for parts and gears?

 

Anyone, I need help identifying another GM rear end ...... B2070, 3726899, GM22
57-58 Chevy?

 

The off-center, single, top mount trailing arm (almost looks like a front suspension "A" arm) makes me think it's a 58 Chevrolet rear end. I believe 58 was the only year that configuration was used. A pic would sure help. I am Butch/56sedandelivery.