I have a 96 Trans Am and I am going to have 3.73's put in. I think I have 2.73's in there right now. I was just curious what else I need to buy for the job to work. I bought some 3.73's off of Ebay , so I have just the ring and pinion. What else do I need to do the job and where is the best place to get it. Thanks

 

Unless your gears are set up for series 1 carrier you will need to buy a new carrier. 3.23 on up had the carrier you need.
I am sure some of these other guys can explain it better than me but I am pretty sure you will need a new carrier.

 

Unless your gears are 3 series gears made for a 2 series differential (check out www.thunderracing.com for Strange gears) then you'll need a 3 series differential. I got mine from SLP for $100. If you get a 3 series differential, you'll also need the ABS reluctor ring for $19 from SLP.

Your install shop should have everything else you need (shims, gear oil, gaskets, pinion bearings). I paid $220 for everything above plus labor. You don't need to spend $90 on an install kit unless you are doing it yourself and believe me, this isn't easy. You have to get them just right with the correct shims.