cmerrick

I'm attempting to I'd the rear diff in a '71 roadster and after researching this site and others(plus books) I'm still confused. The code stamped is 2OA811 13 68 followed by a smaller stamping of RBLT-6.71 rough count of tire rotation vs driveshaft is in the 3.55-3.70 range. What is it?
Thanks

C2C3PO

Are you referring to raised letters/numbers "cast" into the side of the diff housing ? Or are you referring to the "stamping" that is found on the underside of the differential immediately next to the leading edge of where the cover bolts on?
The latter information would be extremely helpful in identifying this rear end providing you don't think someone has gone in there and changed out the original gears already.

cmerrick

These are the numbers stamped into the bottom of the casting

C2C3PO

That doesn't sound right !
You should have two letters (like AW, AX,or LR), followed by a letter (probably W), then likely 3 numbers and then likely a "D" followed by another number.
Is it possible the numbers were misread?
I'm thinking this diff is out of an earlier year car. I'd have to brush up on those codes to be of any further help.

cmerrick

I was under it a couple of times to verify. Took pictures to make sure I was reading it correctly and cleaned the stampings with a pick to make sure something wasn't obscured by dirt.

Mooser

Certainly doesn't look like a 71 code

Going way off course here, what if we say the rear is out of a different year car
2OA811 13 68
For a 68 the codes look all Ax but could be AS for 3:70 - non posi

From the 69 section of the book
The code begins with a number which represents the shift followed by a 2 or 3 letter code for ratio next a date code one or two # for month then one or two for day the year then letter for the plant
2 CAS 11 13 69
So lets say 2 for the 2nd shift
CAS for a 3:70
Nov, 13th 69

Not sure about that rebuilt stamp stuff afterwards

Or it could be a locker combination for the YMCA
Mooser

redvetracr

"OA" is the code for a 75-76 3:08