[docfrahm]

I have a 68 442 with the "O" type rear end -3.08 open differential . I would like to install a 3.73 anti spin differential and an overdrive transmission as my winter project. I think that I have the transmission sorted out with help from Art Carr , but I'm not sure on the differential - is there any interchange among other GM carriers , or is this an Olds only part ? Can I use an Eaton or Detroit Locker that are advertised in Year One or OPGI ? Does anyone have a source for the Olds differential. Thanks

[joe_padavano]

Originally Posted by docfrahm

I have a 68 442 with the "O" type rear end -3.08 open differential . I would like to install a 3.73 anti spin differential and an overdrive transmission as my winter project. I think that I have the transmission sorted out with help from Art Carr , but I'm not sure on the differential - is there any interchange among other GM carriers , or is this an Olds only part ? Can I use an Eaton or Detroit Locker that are advertised in Year One or OPGI ? Does anyone have a source for the Olds differential. Thanks

The Type O is unique to the 67-70 Olds A-body cars and there are no easy interchanges. The Olds specialty houses sell parts, carriers, and gear sets, as do Gevo's and Drivetrain Specialists (DTS).

GM 8.5 O FULL INST, SMALL INST, R&P, YOKE, SMALL PART, GM 8.5 O

[docfrahm]

Joe, thanks for the information and the leads.

[John McGraw]

If you find a carrier, I would be interested in buying your old 3.08 gears. They only make the gears in 3.42 and 3.09 now days. My rear had been sitting so long, the gears were rusty. If I can't find a set of 3.08 gears, I may switch to a 12 bolt Chev rear end. If I do that, my anti-spin carrier will be for sale.


Regards, John McGraw

[joe_padavano]

Originally Posted by John McGraw

If you find a carrier, I would be interested in buying your old 3.08 gears. They only make the gears in 3.42 and 3.09 now days. My rear had been sitting so long, the gears were rusty. If I can't find a set of 3.08 gears, I may switch to a 12 bolt Chev rear end. If I do that, my anti-spin carrier will be for sale.


Regards, John McGraw

John,

As you may know, open and anti-spin carriers use the same ring and pinion gears. Any Type O 3.08 gear set will work for you. Open 3.08 Type O axles are usually relatively inexpensive.

[John McGraw]

Joe,

Yes, I am aware of that, but I have been trying to find a set of 3.08 gears for a while now, with little success. I am hoping that I do not have to buy a complete rear end and the associated shipping just to get a set of gears that may turn out to be unservicable. The rear I have now had sat long enough for the gears to rust, and I did not want to invest $200 in shipping, just to find the same thing on another rear end. I have exhausted my local sources, and have not been able to find a good set of 3.08 gears.

Since I am building a resto-mod, and am not concerned about originality, I may just be better off buying a rear end that has unlimited parts availability and sell my anti-spin to someone who is interested in keeping their car correct. The car I am building now is only about 450hp, so the type O should be plenty strong, but the parts for these things is tough!


Regards, John McGraw

[joe_padavano]

John,

My choice would be a Chevy 12 bolt as well, assuming you can afford one. Here in the mid-Atlantic area these all seem to be made of solid gold.

[docfrahm]

Originally Posted by John McGraw

If you find a carrier, I would be interested in buying your old 3.08 gears. They only make the gears in 3.42 and 3.09 now days. My rear had been sitting so long, the gears were rusty. If I can't find a set of 3.08 gears, I may switch to a 12 bolt Chev rear end. If I do that, my anti-spin carrier will be for sale.


Regards, John McGraw

John,
I'll keep you in mind - I have to see where the budget stands after braces for my 14 yr old. The gears looked very nice when I pulled the cover last fall - odometer was 41,096 at that time. I've put about 2500 miles on this summer with no rear end noises that I can hear - although the 2.5" exhaust and FlowMaster Super 44's are relatively loud. Hopefully the budget works out and I'll get my anti-spin differential and new gears.

[Westley T]

I have a 68 442 3.90 factory posi-trac rearend, it came from a 72,000 mile car. The original 3.90 gears are excellant- the rest of the rear is very-good, there are no alterations at all. the only issue is a broken cover-bolt. price is $1200 firm. contact Westley @ ra5gto@yahoo.com if interested