8.2 GM rear end 3.23 versus 3.90.
 

I am currently selling a 3.90 Richmond Gear ring and pinion set. My body shop put back the original 3.23 gears in my car. If you switch from 3.23 to 3.90, you must use a different carrier? I read something about that if you go above 3.36 you must use a different carrier. My car had been switched to 3.90 gears before my purchase and there have been no issues. If you go back to 3.23 gears, can you stay with the carrier for the higher ratio gears that was in there, or does that have to be switched back?

The 3.36-4.33 carrier is different from the 2.93-3.23 carrier. You will have to find an original since they are not made by the aftermarket.

Will they not even bolt together, or like on mine they put the 3.23 back in it from the 3.90, and there will be issues? My car is not back on the road yet, but I am going to check with them to see if they put the correct carrier in it.

The 3.23 gears will not work with the 3.90 carrier. The pinion will install, but after you put the 3.23 ring gear on the 3.90 carrier the ring gear will hit the pinion when you try to install it.

The 3.36 to 4:33 GM Posi units are getting very hard to find.

Wish now I had not destroyed the 3 Posi units I did before going to complete 2.56 rear
to move the car around and go on trips.

The 12 bolt I blew up was already modified with Auburn Gears and did not last long.

No issues with the 3.36 - 4:33 gears and Posi rears IF you do not beat on the rear axle using slicks. All 3 failed after slicks were installed.

Tom V.

X4 on the 3.36-4.33 carrier not working with 3.23 gears. Installing a set of 3.36 gears would be just fine instead of the 3.23's.
Agree that when you install slicks on an 8.2 rear, the rear becomes the 'fuse' that blows, instead of the tires!