How do I determine what gears I have in order to swap in a posi? I thought I had read that there was a code visible on the diff, or do I have to pull the cover? It's a 70 Cutlass S. Thanks for your help.

 

There is usually a 3 digit code stamped on the top right side axle tube in the area of the break line...Though i do not have the code break downs, if you find it and post it i'm sure someone like jim (monzaz) or brian (507olds) would be able to tell you what it means.

Ofcourse you could always pull the cover, count and divide...not a bad idea just incase the gears have been changed over the years.

 

Thanks for the advice. The gears are original, but I agree I should have a peek anyways. I just bought the car last summer off of the original owner, and he maintained it very well. He kept all of the service record receipts and I don't recall seeing many diff fluid changes anyway!

 

Pull te cover- - GM already did the work for you- Read the ring gear outer diameter of the gear. Keep spinning and wiping with a rag you will find the part number and the tooth count and the year of the gear. OR post all the numbers and will figure it out for you. Jim

JD

 

Thanks Jim. I've got a hoist rented tomorrow!