Need help identifying rear end.

[Stephen R.]

Dug out my "spare" rear end and got the following numbers off of it:

GM 26 (or could be 28)

3725899

F 13 7 (flat screw on left of date and round screw on right of date)

BB 624 (above the first "B" is a smaller "B" but kind of laying on its side perpendicular to the first "B")

What do I have? I believe it's probably a passenger something.
Thanks
Steve

[John H.]

Re: Need help identifying rear end.

Dug out my "spare" rear end and got the following numbers off of it:

GM 26 (or could be 28)

3725899

F 13 7 (flat screw on left of date and round screw on right of date)

BB 624 (above the first "B" is a smaller "B" but kind of laying on its side perpendicular to the first "B")

What do I have? I believe it's probably a passenger something.
Thanks
Steve

Steve -

The 5899 center section is for an open (non-Posi) axle, and the casting date (June 13, 1957) and assembly date (June 24th) make sense. What doesn't make sense is that the casting date format is for a Saginaw casting and the ratio code (BB, 3.36:1) is for a Buffalo-built passenger car axle, and Buffalo cast their own center sections, with a 2-digit format for the year in the casting date. How did that happen? Who knows. Appears to be an open 3.36 axle center section, which is fully interchangeable between '57-'62 Corvettes and '58-'64 passenger cars.

If I've missed something here, Tom Parsons will be along to correct it.

[Stephen R.]

Re: Need help identifying rear end.

John:

Thanks for the info. Of all of the numbers that I posted above, the "BB" was the most difficult to read. The top part of the first "B" appears to be non-existent and the second "B" is almost totally gone. I think I read them correctly but I can't be sure. Again thanks for the info.
Steve

[John H.]

Re: Need help identifying rear end.

John:

Thanks for the info. Of all of the numbers that I posted above, the "BB" was the most difficult to read. The top part of the first "B" appears to be non-existent and the second "B" is almost totally gone. I think I read them correctly but I can't be sure. Again thanks for the info.
Steve

Steve -

If that ratio code was "AB" instead of "BB", everything would make sense; "AB" is the Corvette (Detroit Gear & Axle) 3.36 (also used on passenger cars), and "BB" is the Buffalo 3.36 code, used only on passenger cars.