txrob779

Howdy fellas,

I have some misinformation. I defintalely has a 12 bolt under my 53,800 mile Cutlass and I was told many years ago it was a O code however I was replied to here saying that it prolly was NOT a O Type. So, I am out scraping crude off the diff trying to find some codes.

Can someone link me to a list of numbers and where to look? I know where to look for the 67-70 O Type but that is it.


BTW my car was built the 4th week of July 1966.
February162014003_zpsf324e29f.jpg


Thanks,

(pics to come soon, having camera issues)

Fun71

One of the easy ways to verify an O-Type is to pull the cover and see if it has 10 bolts holding the ring gear on.



I did find these pics of the O-Type 12 bolt and the Chevy 12 bolt covers. you can see there is a very definite difference between the O-Type on the left and the Chevy 12 bolt on the right.





I found this on Supercars Unlimited's web site showing the difference in the covers:

txrob779

Well mine def has that plain cover....as far as finding some codes, gosh DAMN I am scraping and wire brushing all over this sum***** looking LOL. I cant find nothing LOL

joe_padavano

Olds started using the Type O axle part way through the 1966 model year.

monzaz

Look on the back of the PASSENGER tube - Between the spring perch and the cast center section. Most of the time it is Up Side Down too. Jim

txrob779

I cleaned, wire brushed and WD40'd that passeger tube but can't find a stamp yet. I'll keep looking.

Thanks fellas

Fun71

That stamp will just be the gear code. If you're wanting to determine what make rear it is you will need the casting code off the center section.

Gear code stamp on tube from a couple of my O-Type 12 bolts:

Standard 2.56 open
1970O-Type12boltcodelocation.jpg

Optional HD 31 spline 3.42 open
196812bolt342HDopendiffTLcode.jpg

txrob779

Cool thanks