What kind of decrease in milage can I expect if I go from the stock 3.08 gears to 4.10 gears?? I have the 4x2 4.2 V6 with stock size rims and tires.

 

I have the 4.6L with the 3.08 gears as well. (automatic) i want to upgrade to the 4.10 but i was told i'd lose my overdrive. is that true?

 

you won't lose your over drive it just will not be as effective as if you had the stock 3.08 gears. The motor will be at a higher RMP while the truck is moving at a slower mph. In order to go the same speed as with the stock gears while cruising the motor will have to be at a higher RPM. Hrmmm.. ... hope that helped .

 

3.08 to a 4.10 that a pretty good swap I'm sure your truck has some get up and go now.