what gears do I have?

**crawdad369** · 11-20-2008, 10:12 AM

I have a stock 98 Z28 A4 runs 2k rpms at 70 which seems really high to me. my truck runs 1.6k at 70. It feels like the trucks have a tall od compared to these cars. Anyway, any idea of my stock rearend gear?

**SSwt00SS** · 11-20-2008, 10:20 AM

check your door codes and see which of the following you have...

GU2 - Axle Ratio 2.73, Rear

GU4 - Axle Ratio 3.08, Rear

GU5 - Axle Ratio 3.23, Rear

**crawdad369** · 11-20-2008, 10:37 AM

wow it says GU2 but dang 2.73's turn over 2K at 70mph .... cant b right

**2001NBMZ28** · 11-20-2008, 10:48 AM

Can't always tell by the door codes, my car came with 2.73's but I changed to 3.42's. 2K at 68 = 3.23's assuming stock tire height and speedo is correct. Try playing around with the calculator at www.f-body.org/gears/

**SSwt00SS** · 11-20-2008, 10:49 AM

4L60E gear ratios: 1st 3.059, 2nd 1.625, 3rd 1.000, 4th .0696,
Reverse 2.294.

i believe these to be what are in the F-body A4's...

**c5z28** · 11-20-2008, 11:24 AM

it be right 2000 is on the money

**c5z28** · 11-20-2008, 11:26 AM

Originally Posted by 2001NBMZ28

Can't always tell by the door codes, my car came with 2.73's but I changed to 3.42's. 2K at 68 = 3.23's assuming stock tire height and speedo is correct. Try playing around with the calculator at www.f-body.org/gears/

I am looking into getting gears, 3.73's seemed a little to highh but I was wondering about the 3.42's. what your tach at 70mph or so? e.t difference etc.

**2001NBMZ28** · 11-20-2008, 11:59 AM

You can plug in different gears in the link and it'll tell you the differences in RPM at different speeds for each. If doing gears I'd go with 3.73, I went with 3.42 because I got a good deal on a complete rear out of a M6 car. If you already have 3.23's it's not worth changing to 3.42's.