hey guys so i found out that i have some weird rear end in my 1969 Oldsmobile cutlass and was wanting to know if i can get a posi carrier for it. The numbers are 402227 and it says cfd on it and i think its a 8.4 ring gear and i counted the gears and it has 278 gears in it currently. Im wanting to know if there's anywhere that sells just gears for this rear end or a posi carrier and gears for it. thanks in advance

 

Does the rear have 12 bolts holding the cover on and 10 bolts holding the ring gear to the carrier? If so, it is likely the original O-Type rear that came in the car from the factory.

The O-Type was used from 1967 to 1970 and is not really "some weird rear end" although it is different from the other rears of that era, just like the 8.2" Chevy 10 bolt, the 8.2" Pontiac 10 bolt, the Chevy 12 bolt, etc. are all different. There are options for gears and posi once you are certain what rear it is.

 

Ok thank you. Yes it's a 12 bolt cover and 10 bolts holding ring gear on. Where would I fine posi unit for this and gears? You think summit would have something? And I'm kinda try to do this on a budget because if I wasn't then I volt just get a chevy 12 bolt to put underneath it.

 

Posi and gearsfor the O-Type will not be found at Summit. Check with monzaz or 507olds here on the site as they are the resident experts and can set you up with the parts you need.

Be aware that the O-Type parts aren't cheap and setting up new gears takes someone with knowledge and experience, so it may be more economical to buy an entire 8.5" 10 bolt rear with posi and the gear ratio you want.

 

The cheapest route you'll find is buying a posi rear off craigslist like I did. 3.55 setup for $500. Keep in mind that for some reason, used 4.11 posi diffs go for $1200+. You'll easily spend $1200 in parts plus install to add a posi and gears to yours.

 

ok thanks guys. When you say 3.55 setup on yours what do you mean? I have been looking for a complete rear end because i feel like it would be the cheapest rout but all i can find relatively cheap is a ford 9" and then i would have to have someone connect brackets and stuff. If i found a setup for $500 i would definitely buy it. i can get a nice ford 9" for like $100 but does anybody no anybody that makes them fit a cutlass?

 

The rear from any '68-'72 GM A body is a direct fit:
Chevy Chevelle, Malibu, Monte Carlo, El Camino
Pontiac LeMans, Tempest, GTO, Grand Prix
Buick Skylark, GS
and of course, any Olds Cutlass

 

Quite simply, not for under about $3k. Its a massive undertaking unless you do it for a living. Rig up a fixture to get the mounts at the right angles, in the right locations. Weld them, with all seals and oil cleaned out of the diff. Then install bushings and build the diff. Not simple, not cheap. Buy a used A-body diff and bolt it in. They don't last forever, but they're really pretty tough.

 

Ok thanks didn't know it was that Hard. Are you talking about the whole rearend when you say diff or the carrier. Idk I can't find anything on craigslist but I guess I'll just keep looking. Thanks guys! Thought about just putting gears in and welding it so I could get posi faster but we all know how that usually turns out lol

 

Where are you located ?