I recently had problems with rear in my 99 camaro. when I went for parts at the GM dealer according to the vin for ordering, the rear shows gu6 from factory but the car has a gu4 and also codes in the door show it to be a gu4. Is this a fluke or something to be concerned about? Vin definately shows gu6 with door label showing gu4

 

The VIN has nothing to do with the rear axle ratio.

I'm sure it means something else, use this to find out what it means:

http://www.chevy-camaro.com/chevy-ca...fourth-gen.asp

GU4 = 3.08... never seen those gears before, I'm guessing it's only in V6es?

GU2 Axle, Rear 2.73 Ratio
GU4 Axle, Rear 3.08 Ratio
GU5 Axle, Rear 3.23 Ratio
GU6 Axle, Rear 3.42 Ratio
G80 Axle, Rear Posi-traction (Limited Slip)

 

yes it is a v6. thanks for info. still researching why the numbers don't match

 

It's not going to, the vin doesnt have anything to do with the rear axle gears.