i have a little bit of a problem. i have a 1998 trans am with a 2.73 gears and a carrier that cand hold who knows what. i work up at a chevy delear and when i looked up the parts it says that i have a case that will hold a 2.73 which makes sence but below is another case that says that it can hold a 3.23 and a 3.42 and the part number is the same. now i was going to get a 3.73 out of a s-10 pickup truck which is the same part number as in the performance part book for a 3.73. i was just wondering if any one has run into this problem. i was aslo wondering if the case on my 1998 trans am was for 3 series gears but my 2.73 was made for that carrier??? all parts are GM no aftermarket.
please let me know if the case that i have will work with the 3.73 gear out of the performance catalog (which is the same as a s-10 gear).

also my car has posi limited-slip and NO traction control ( 7 5/8 case)

 

No, your stock posi will not work with GM parts. You need a 3.23 and numerically higher case to run the 3.73's.

 

If you don't have a good knowledge of rear gears, I would STOP and RETHINK this project.

 

i understand that i need a 3.23 or highter but why is it when i look up a case for my car that is for a 2.23 or 3.42 the part # and or part is the same as the one on mine ????

 

The 2.73 gears came in the "base" model A4 Trans Ams, without the "performance axle" option. The 2.73 gears will show on your build code tag as "GU2". You will have a 2-series carrier in the rear. If the original buyer opted for the "performance axle", the build code tag will show "GU5", and you will have a 3-series carrier. Or, if your car had been an M6, with the standard 3.42's (GU6), it has the 3-series carrier. If you want to go from a 2.73 to the 3.73's you either need to switch to a 3-series carrier, or buy the gears from a company that makes 3.73 gears that fit in a 2-series carrier.

 

I don't know, But looking for a GM part number will be useless if you go and buy one from an aftermarket company or ebay. If you think your GM discount will save you money on this part I highly dought it.

 

would it be ok for me to use a case off of a 1999-2002 trans am even tho i have a rear end that had a (gu2) in it?????

because the 1998 case's that are listed dont have one that hase both posi and NO traction control that is a 3 seires

or can i get a case that has traction control eventho mine does not will it mess it up??? i think it will b/c the reluctor ring for the abs???

please let me know what case i should get to get this gear in my car. and also i have credit that GM has of mine so i will get GM stuff.

 

Why dont you just buy 3.73 gears for a 2 series carrier??

 

look on ebay for a series 3 carrier sometime u get them cheap

 

Thats what I did and so far so good 3 years running Richmond
Gear part# 49-0007-1

 

im glad to see that about the richmond gears, thats what im gettin put in my car tomorrow

 

Try looking at Thunderracing.com, that's where I got my rear end gear package from, I had the 2.73 and went to the 3.73's, it's my understanding that the ring grear is thicker.