As far as I know, my car is stock. All I've done so far is cai and i was wondering if there was any way I could figure out what my gear ratios are. I had the car up on a lift yesterday and I was looking at the rear differential but I had no idea what I was really looking for so it was a lost cause
But yeah I guess I just want to know the simplest way to figure out what gears my 93 z28 a4 came with stock.

 

jack the back. mark a hash on the tire and drive shaft. spin the tire 1 full rotation while counting the rotations of the drive shaft. 3 ~12 rotations should be 3.42

 

If your shifter goes to 1st you have 3.23s... If it only goes to 2nd you have 2.73s.

 

Just cruise on the highway and see what rpms you have.
I've got 3.23s.
4th gear at 60mph=1900 rpm
My V6 Camaro came with 3.42s.
4th gear at 60mph=2000 rpm
So I'd say if you've got 2.73s you'll be looking at 16-1700 rpm.
- and you can't shift a 2.73 car into first with the shifter, unless the little thing that stops it has been cut off.
Also, I believe GU5 is the code for 3.23s.

 

shifter goes to first...so based off that i can assume I have 3.23s?

 

Look in your glove box, and look for GU5 = 3.23 gears, if anything you can also check your shifter plate, it should have P N R D 3 2 1, is you have these you have a 3.23 rear end.

 

In your glove box you should have a code list that tells you all the options on your car originally.
If you have one of these codes thats the gear you have.
GU2/2.73
GU4/3.08
GU5/3.23
GU6/3.42

Here's a complete listing of codes: http://www.fbodymotorsports.com/9302rpocodes

 

Yes.