Have a 99' F150 w/5.4, 3:73 LS rear end, 4x4, auto tranny, towing pkg. Driven 90% in town getting about 10 mpg max., sometimes less. Would 3:55 gears get that much better mileage? How expensive to swap? Would transmission shift points have to be changed, and what about resetting the computer? Any info appreciated. Thanks in advance. P.S. Love the truck otherwise.

 

not worth it.

 

I agree, not worth it. You would actually want to put lower gears in the truck for town usage. The motor would not work as much to get the mass moving. Just the opposite when driving all highway, you would want higher gears. With the money you would spend on a gear swap, you could put in the fuel tank. I doubt you would see more then a .5 mpg gain changing gears.

 

I have 3.31 gears in my 2wd and most everyone here with 3.73 and 4wd gets as good or better mileage than me. Since you have two axles to change out you'd probably be looking at $1200 or so. You can buy a lot of gasoline with $1200.