Thread: IDing a rearend

Tweet

How do I tell what rearend I have? Where are the numbers usually and is there a site to match the numbers up? I just got an old used rearend from my ex father in law that came from a trailer he made. The rearend has all the gears in and rolls smooth. Just want to know what manufacturer it is and what size gears.


Thanks
Joker51

Do a google search.....there are hundreds of sites. A lot have
pictures.

problem is without knowing the manufacturer its too general of a search to find anything, or at least it has been for me so far.

Narrow the search by measuring the wheelbolt pattern. See if it has a back plate, or if the carrier comes out the front. The shape and number of bolts holding the rear cover or carrier ass'y in place is a clue, too.

Well I just checked the rearend and it looks like a GM 10bolt. Not sure what year or anything as I can't find any numbers, can anyone tell me where the numbers would be for a 10bolt rearend? And where I can look it up at?

BTW its 50" from backing plate to backing plate, perfect replacement fit on the 49 plymouth

Originally posted by joker51
Well I just checked the rearend and it looks like a GM 10bolt. Not sure what year or anything as I can't find any numbers, can anyone tell me where the numbers would be for a 10bolt rearend? And where I can look it up at?

BTW its 50" from backing plate to backing plate, perfect replacement fit on the 49 plymouth

If it's a GM, get out your wire brush and clean off the area on the bottom of the housing right below the cover. If you find some numbers they can be translated to tell you which rear end it is, ratio etc. I don't have the data at my finger tips but can find it for you. Post the number and I'll look it up.

I hope if this site allows links, if not, someone let me know before shooting me. www.oldsmobility.com/10bolt-tech.htm It's primarially an early Olds site but has info on all GM axels. Happy hunting

Here are 2 pics of the cover, is this the GM 10 bolt?
http://www.clubhotrod.com/photopost/...sort=1&thecat=
http://www.clubhotrod.com/photopost/...medium&thecat=

http://www.nationwideparts.com/differentials.htm

My guess is it's a GM 10 bolt, but since you have the cover off you can measure the ring gear to be sure of the size. While you're in there count the teeth on both ring and pinion to determine the ratio, and look for part numbers on the gears. You still need to find the casting number on the housing to be sure. Clean it up good and look on the bottom close to the cover, or on the sides near the fill plug.