View Full Version : 3.73 gears

05-03-2012, 05:51 AM
Hey guys I have a 99 trans am with 2.73 gears. I want to switch to 3.73 gears soon. Ny question is do i need to change any thing else besides the ring and pinion in tbe stock rear end or what all needs changed? Thanks for the help.

05-03-2012, 11:54 AM
It all depends on how many miles the rear end has

05-03-2012, 12:38 PM
You will also need tuning to correct the speedometer and shift points.

05-03-2012, 01:08 PM
I'm in the same boat as he is. What's the difference between 2 series and 3 series? Idk which ones to get

05-03-2012, 01:26 PM
If you have 2.73's (RPO GU2) you have a 2 series carrier and normal 3.73 gears WILL NOT work.

If you have 3.23's (RPO GU5) then you have a 3 series carrier and normal 3.73 gears WILL work

If you have a manual you have 3.42's and the 3.73's are fine.

If your car comes with 2.73 gears and the 2 series carrier you must order "Thick cut" 3.73 gears specifically made for 2 series carriers. I know stocks them.

05-03-2012, 01:51 PM
^^ awesome appreciate. Sorry if I intruded op

05-03-2012, 01:52 PM
Find out what series you need and buy a gear swap installation kit - new bearings,shims, etc are included. - That is what I did when switching that same gear ratio. Doesn't hurt to freshen it up.

05-03-2012, 06:08 PM
don't want to hijack but how do you find out what series carrier you have?

05-03-2012, 07:21 PM
Carrier is easy. See my above post. If you have 2.73s you have a 2 series carrier. 3.23 or 3.42 geared cars are 3 series carriers. Knowing that is all that matters really when picking the proper type gear.

For performance applications 3.73s are recommended for A4 cars, some M6 owners may choose 4.11s. If you do a lot of highway driving you may want to opt for a ratio around 3.50.

05-04-2012, 07:57 AM
Thank you for the reply, very much appreciated.