Gear ratio swap on 2003 C5

[ab8081]

I'm ready to trade my 2000 C5 for a 2003. Ive found the exact one I want except for the gear ratio. It has 2.73's. I'm trying to deal with the salesman about installing 3.15's. (the performance option listed so I know it is offered). My dealer says it can't be swapped. Says the computer won't allow it. I checked with another dealer and he said it can't be done due to emissions. Am I missing something. Does anyone know if this ratio change can be performed? I think I'm being misinformed.

 

[DkBG]

Are you talking about a brand new car . Did you want them to swap a brand new rearend for another brand new one . If everythings new , wouldn't it be easier to get a different car that is exactly what you want ? Cliff

 

[c4c5specialist]

HI there,
The mod can be done per EPA guidelines, as long as certain parameters are followed.
First, you must be able to find a VIN of the exact powertrain as yours, except for the 3.15 axle that you want.
Then, you must purchase another computer, and install the programming for the car with the 3.15 axle ratio.
Per EPA guidelines, as long as the mod does NOT affect the emissions levels in anyway, which it does not, because you are using the calibration directly from GM, it can be done without fear of problems down the road.
Allthebest, c4c5