71-72 Oldsmobile Rear Axle Carriers

[anthonyP]

Hello.

I've seen both Oldsmobile and Buick 8.5" 10-bolt rear axle carriers in stock 71-72 Cutlasses & 442's, both in open and limited slip versions. The Oldsmobile carrier with the round axle cover with the brow from the 12 to 3 position, and the Buick carrier with the scalloped ")(" axle cover at the 9 & 3 positions. The Buick carrier also has the single rib and the Oldsmobile have the parallel twin ribs.

Supposedly the gears and limited slip units are the same in either the Olds or Buick carrier. It seems the only difference is the oiling passages that travel near the axle tubes on the Olds carrier and is not present on the Buick carrier - which is why the Buick axle cover with the scallops cannot be used on the Olds carrier.

From what I was told and seen, all of the Lansing built cars received the Olds carrier, as well as those at the Framingham and some other plants. All others received the Buick carriers, no matter if open or limited slip.

In your opinion, which is the better of the two 8.5" 10-bolt carriers - the Oldsmobile or the Buick?

Also, do you have any Oldsmobile 8.5" 10-bolt limited slip rear axles, with 2.56, 2.78, or 3.42 gears, and the round axle cover/twin ribbed carriers? These are for multiple cars.

Thank you,
Anthony

[monzaz]

Anthony, There is no difference and we have no opinion on what is better. It has been proven over time that the axle bearings do not stave either way.
Both Buick and Olds have double rib. The single rib was 8.2 only NOT 8.5. That is one of the dead give away for the difference.

As far as actual factory posi 10 bolt 8.5 stamped posi. WE have none. We can make any of the rears we have posi - The axle tube is just not stamped original posi. Corp. 8.5 never had a 2.78 ratio... it was 2.73 ratio.

Jim

[anthonyP]

Thank you Jim for the clarification.

I will check the other sections of the website to determine the cost for an 8.5" 10-bolt with 3.08 gears, limited slip, in an Oldsmobile carrier. As well as the same except for 2.73 gears.

Thanks again,
Anthony

[monzaz]

We sell complete 3.08 or 2.73 stock reconditioned open or posi rears if you need pricing. Everyone wants them so the prices are getting higher each year... Jim