Curious to what extent gas mileage will be decreased with a gear change from 2.73 to 3.42 on the highway. How bad will it hurt the gas mileage? LT1/A4 on highway with overdrive cruising usually at 65mph. I am getting pretty good mileage on the highway now despite several mods. When I stomp the throttle pedal though it really sucks it down like it is supposed to. I have pcmforless.com custom chip tuning by the way and my highway cruise mileage also got BETTER with the new tuning somehow.

 

It would get worse on highways. The higher gear # you choose the higher rpm it'll use for the same speed.

 

around town tho my mileage wasnt bad with the 3.73 , on the highway a lil worse , I now get 18.8 with all my mods. After the stall tho around town sucks real bad , like 11 or 12 !!!