I am wanting to swap out the 2.73 geared rear end in my 1998 Trans Am for a 3.23 geared rear. What all do I need to know? My car has traction control if that matters. Do I need to find one from another 1998 model, or will other years work too. I know some years that were 3 channel and other 4 channel I believe. If someone could explain what this exactly means I would appreciate it. Also, are the 3.23 posi rears from the V6 cars the same as the LT1/LS1 3.23 rears? Thanks in advance!

 

I'm assuming you want to swap the complete rear axle assembly, and not just the carrier/gears.

If the car only has ABS (no traction control), it uses a 3-channel system.... one sensor on each front wheel, and a 3rd sensor on the top of the differential housing, reading a reluctor wheel mounted to the differential carrier.

If the car has ABS + Traction Control, it uses a 4-channel system, one sensor and a small reluctor ring on each wheel. The rear sensors are on the backing plates at the ends of the axle housing, with reluctor gears pressed on the axles behind the hubs.

If you have TCS, you need to swap in a 4-channel rear from a car that has TCS. You can't use a 3-channel rear axle assembly. It doesn't matter what year you get it from, although it would be easier to get a unit from a 98-02 model, so it will have the same disc brake setup used on your 98. The 93-97 cars have different rear brakes, and you would have to swap the brakes from axle to axle. There are no TCS 93 or 94 cars, so that would limit you to 95-97.

If the V6 got the performance rear axle, I believe its a 3.23 ratio with a limited slip rear, and I assume they threw in the disc brakes, but I'm not sure.

 

Thank you very much, that is a big help. Is the job very difficult? How long does it take on average?

 

You should be able to complete the swap in 2 hours or less. I have an online guide to doing a 10-bolt to 12-bolt swap, but most of the steps are the same:

http://members.aol.com/InjuneerZZ/Strange12.htm