yellowone

These are the rear end numbers on my 1972 Cutlass Supreme. Need help to see if they are "matching" to my VIN. The last numbers of my VIN are 129999.

Fun71

I have never seen a rearend with a VIN stamp on it. They have a code for the gear ratio and posi/open carrier, the manufacturing plant, and a date code.

Your picture decodes as:
SA = 2.73:1 ratio, open carrier (non-posi)
B = Buick plant
288 = day of the year manufactured
2 = I don't know what this means.

yellowone

Thank you for the help. Buick, wow. Wonder if this has been a replacement? My transmission and engine block match the VIN, was hoping the rear end was too. Thank you so very much for Decoding it for me. Hopfully I will have time to upload pics of the car and fill out my bio soon.

Fun71

No, not a replacement rearend. There were multiple GM divisions making the corporate 10 bolt rears and Buick manufactured rears were frequently put in the Olds Cutlass from the factory.

Allan R

The rear axle is not part of what most people call 'numbers matching' for the simple reason it's an easily swapped out part, much like cylinder heads. The SA axle was common for 72 Cutlass S and some Cutlass Supreme's. What factory and model is your car?

yellowone

Factory was Arlington, Texas. Cutlass Supreme 3J57H2R First7 digits of VIN.

Allan R

Which is exactly what I posted on your other thread. The rest of the VIN (which is not really secret) is the production sequence at Arlington. All assembly plants for A body started at sequence 100001. Judging by your build date and knowing that Arlington wasn't really a high production factory, I'd guess it to be somewhere in the range of 1020000 to 104000? Maybe less.

Just an FYI, my car was built at Lansing and the axle code was O and ordinal date was 101 which was exactly the date my car was on the final assembly line. I have the documentation from GM showing when it rolled off the production line on April 10, 1972 and how it was equipped, where it was sent, and how many were sent there.

anthonyP

From what I understand and have seen, the 71/72 Oldsmobile A-bodies built in Lansing and Framingham received Oldsmobile axle housings, and those built in Arlington and Fremont received Buick axle housings

11971four4two

10 bolt 8.5
is there a large letter A cast into the front
towards the engine center section??

monzaz

Allan R

not on mine. 72 10 bolt 8.5

Fun71

Oh, I just assumed the B was for Buick.

So as to not make any further assumptions, how do the numbers on my 1971 rear decode?

Allan R

Kenneth, is your car an Arlington car? If yes I'd guess Arlington, 2nd shift ordinal date March 9, 1971

Fun71

Nope, Lansing.
R2 = 2.56:1 ratio,open differential

I was referring to the other numbers. I had assumed the B in the OP's picture meant Buick and was wrong, so I didn't want to assume the first letter/digit in my number was an O to designate Oldsmobile.