Thanks to all the posts and the excellent info provided! At my own risk I will add new wrinkle to the conversation. I understand there are aftermarket spacers that can be used on the ring gear(Mr. Gasket)to allow series 2 gears to be used on series 3 gears. Any info on if these work well and if they may be used from a series 1 to a series 2 posi unit?
Hello Quenton! I just bought a posi unit from an A body BOP. Are you suggesting that if it came from an Olds or other it may not work on my 69 bird? If you have info please pass on.
OK fellas. Well they say the memory is the first thing to go. 2.54,2.78 what ever. I had to climb over sh*t and under some other sh*t but the set I have says 14 39 GM 1 68 BA(2.78) on the edge of the ring gear. I'm still gonna pull the cover and measure my 3.23 this weekend, if I get the time. The deal is too good to let go and not be sure. So I've had my 3.23 rebuilt already and the question is if I install a stock posi unit will I have to reset the ring and pinion mesh spacing?
I am still looking into it, but from what I know, the Olds 10 bolt rear is different from the rest of the B-O-P clan. If you have a differential case carrier gear housing thingy that looks like this:
With the following numbers : 671, 672, 673 or 588 (673 shown) I can almost guarantee that it won't fit a Pontiac rear end. this is the Olds A-Body 10 bolt posi differential case, and it is different from Buick and Pontiac.
What I was also referring to in my previous post was the 12-bolt looking rear end that is actually a 10-bolt. As most of us know, you can tell a GM 12-bolt just by counting the number of bolts that hold the cover on to the housing. NOT true in the world of Dr. Oldsmobile. In the late 60's and early 70's, they stuck a whole bunch of 8.5" 10-bolt rear ends (that are different, incidentally, from the second gen 8.5" 10-bolt) under Cutlass, 442 and F-85 cars with 12 bolt covers. These are NOT the 12 bolt A-body rear ends that are rather prized in the A-Body world, whose inner workings are the same as the 12 bolt Camaro rear end.
OK. Screw that. They say the cone type(stock) posi unit that came in Ponts are not rebuildable and after 35 years they are mostly all wore out, I would think. So I'm gonna take everyone best advise and save up for the powertrax unit. Around $400 I think. I saw one installed on TV the other day. Took about an hour and looked like a piece of cake. No real adjustments have to be made.
Ha Ha Ha An hour and a piece of cake. That's a good one! Try 4 hours and you better know what you are doing, seriously. Everything looks easier on TV. Jim
Saw the same thing on HorsePower TV. Unit is made by Eaton I think and was a piece of cake. Only took about 10 minutes of TV time. Remove your spiders, stuff this little gem in and you have a posi. You don't have to remove or re align anything else. Replace the cover, add oil, add posi lube and go make twin stripes on the tarmac. They did the conversion into a 66 or 67 Chevy wagon.
