Ok I have a spare rear end(from 91 formula) that had 3.23 posi so its 3 series carrier.

My 83 Trans Am has 3.73 open diff so its a 3 series carrier too.

I want to remove the posi carrier and put it into my 83 Trans Am.

My two questions are:

Will I run into any problems swapping these such as with side gear spline #'s.

And when I pulled the posi carrier out, I noticed that there were NO SHIMs at all, just 1 solid washer(spacer)on each side. I want to keep the 3.73 gears that are already in the trans am so I have to remove the ring gear from the open carrier and put it on the posi carrier. My question is, can I get away with not removing the pinion gear since I'm keeping the same gears, and do you think I would be ok just transplanting the carrier and keeping whatever spacers/shims were in it with the open carrier? I know I'll still need to check backlash and contact pattern, but it seems to me that if I keep the same gears that I should get away with just keeping the spacers/shims that are in the case in the same spot, and not even mess with them. After all its just carrier being swapped, and not the gears.

Tell me what you think and any advice is appreciated.

 

IF you are very very verrryyyyy luck, you might get away with reusing the old shims when you pop in the posi carrier...

All you can do is try. pop it together and check the contact


Other than that, like you said, the only other holdup would be the axle spline count. Its either going to be 26 or 28, but you can just swap the axles if they are different spline.

 

there's no need to remove the pinion, just swap ring gears and check/set back lash. you have to reuse the original shims, or at least keep the total shim thickness. you may need to change the arrangement from side to side to get the back lash set to spec. you might want to check the contact pattern just as a secondary check but th e back lash is what you need to worry about. your axles will be differant splines but you already have a set to match so just swap axles too.