[srd1]

Hi,
I have a differential for a 10 bolt with GM 4:10 gears on it. The only numbers I can find on it are stamped in and they are J211 269. I can't find anything even close to this to figure out exactly what it is. Anyone know what this is?
THANKS!!
Greg

[Jon]

First check the Hotrodders Knowledge Base. Here's the relevant category: Transmission-Rearend Technical Data.

[jimfulco]

Any numbers stamped on the outer edge of the ring gear?

[73oldsman]

These sites may help; http://novaresource.org/axle.htm
http://truckparts-specialists.com/ca...ture-guide.htm

[lust4speed]

This guess will probably end up way out in left field but here is my guess:

the 10 bolt cover could be an 8.2 or 8.5 Chevy, or it might be a GM large car rear end. It is not a BOP 8.2 axle since there was no 4.11 ratio that I know of (3.90 then 4.33).

While none of the charts support it, it looks like the J211 is a date. The J would be October, 21 would be the 21st, and the 1 probably is for 1971 (or maybe 1981, 1991?) If it is a BOP big car, it would not be 1961 because they used a carrier like the Ford 9" until 1964. The BOP big car had a 10 bolt cover and a 12 bolt ring gear.

So what is stamped on the ring gear, and what is the distance between backing plates?