rocn7roc

Hi I have a 91 Rs without posi and would like to install a 4th gen diff in my housing,need to know if it will work, I am a mechanic so the install will not be the problem. I believe I have the 28 spline axles and am looking at diffs on ebay from late 90's z28 like a eatin posi, will it physically fit? if not what years posi will work in my housing Thanks Mike

Ozz1967

iTrader: (4)

Yes, they'll fit.

I have an 84 Trans Am. Using my original housing, I swapped out to 28 spline axles and installed a Zexel Torsen diffrential which is what came out in the 2000-2002 Camaro's and Trans Am's.

big gear head

You must know what your gear ratio is and what series differential you are buying. You must use a 2 series with 3.08 to 2.14 gears and a 3 series for 3.23 to 4.56 gears. Also know that this is not a simple bolt in job. You must set the backlash and bearing preload when changing the differential. You must check the backlash on your gears BEFORE removing your old differential so that you will know how to set it when you put the new one back in.

Ozz1967

iTrader: (4)

There are also some 3-series carriers that came with a 3.08 but not very many. He said he was a mechanic so I made the assumption he knew how to do the instal.

rocn7roc

Thanks for the imput ,I have 2.73 non posi want to go to 3.23 or prefer 3.42,so it looks like my housing won't work. I guess my 2 seiries won't work then for 3.42 setup . Is that correct. Thanks . Mike

rocn7roc

Thanks ,what gear ratio did you have and which one did you go to,big gear head says I need a different series housing .I have 2.73 non posi and want to go to 3.42 and I have the 28 spline axles already,would the eaton posi fron 99 camaro work also? Any other members care too chime in on this also.Thanks Mike

big gear head

Your housing is fine. You just have to use a 3 series differential for the 3.23 or 3.42 gear. The 3rd and 4th gen Camaros never had a Eaton Posi. The '82 to '97 Camaros used the Auburn differential and the '98 to '02 used the Torsen. There were a few 3rd gens that got the Eaton Governor Lock, which should be avoided.

Ozz1967

iTrader: (4)

If you got the ring and pinion gears from the new differential it'll work just fine. The 2 and 3 series carriers are spaced differently so the ring and pinion gears are sized differently.

ALso, if you get a new gear set, don't get Richmond, I've had a bad experience with them. I'd definitely go "motive' or another company. ALso, you want "Street" gears, they're made a little differently and are built to handle every day use.

rocn7roc

Thanks for the imput I am planning on going ahead and buying the complete posi diff with gears attached from a 4th gen and installing in my housing ,I have the indicators and knowledge to to this I 60 year old Journeyman heavy machinery mech. Thanks All

rocn7roc

Thanks I got the same torsen for the 91 RS should I buy the 99-02 kit or the 86-98 bearing install kit? Thanks for your help Mike?

big gear head

The '99-'02 kit will have the wrong pinion seal in it. Get the kit for the housing that you are using.

Ozz1967

iTrader: (4)

itsjoeyjoe

Did you also you the axels from the 2000-2002 Camaro? Or did you have to order new ones
Im currently doing my 7.5 10 bolt build

sofakingdom

iTrader: (1)

If your 10-bolt is for a 82-92 Camaro or Firebird, then no, you can't use 93-up axles in it. They're quite a bit longer.