Trying to figure out what my rearend is and what it possibly came from. It's in my 67 442 that I just recently purchased. Seems to be the correct width for the car.


The only stamping I can find on it is OS on the passenger side.

 

Look for the casting number on the lower right front. That will identify it.

 

Your axle is a Type O, and despite the twelve bolts on the cover there are only ten bolts holding the 8.5" ring gear to the carrier. Type O axles were factory installed in 1967 Cutlii. The part number for the housing is the same for 1967 and 1968 cars, by the way.

 

That means it could be original to the car. What spline axles would it have? Tomorrow I will look for the casting number.

 

Axle spline count depends upon the gear ratio. The standard duty was 28 spline axle shafts, and the Heavy Duty option was 31 spline axle shafts. HD was available only on the 3.42, 3.91, and 4.33 ratios.

 

Casting number is 394139 so looks like it's the type O for sure. What gear ratio is indicated by the SO stamp on axle tube?
Thanks to everyone for helping me!

 

No SO code but a SQ is a 3.08 open unit.

 

Did some more googling and looks like it is a 3.23 with 28 spline axles from the factory.

 

Checked again but I can't find the tail to make the O a Q unless it was stamped wrong. But 3.08 or 3.23 is fine for the 455 under the hood.

 

Do your self a favor and invest in a PIM aka assembly manual. It has the answers to a lot of your questions. Hairy Olds on here has the best on the market. PIM = Product Information Manual and was used by assembly line workers.

 

Went back and took a closer look at the stamping and it's definitely SC, not SO. Rotated wheel and counted driveshaft turns confirming 3.08 gear and one-wheel peel.

 

do you mind sharing the details for this axle? I just picked one up (it just has SC stamped) and trying to figure out if it would work for my 72 chevelle