change rear axle ratio from 3.55 to 2.92 to improve gas milage

[fernbeebe]

Will changing the rear axle from 3.55 to 2.92 increase gas milage in my 2003 ford explorer XLS? If so where can I get the new or used parts? What used parts might be interchangable? Thanks cf

 

[Tbars4]

welcome here...who or what may i ask helped you come up with 2.92 gears???...i'm just curious....:scratch:

 

[carlover]

stick with the 3.55's. If you go to that kind of gear ratio your mileage will go to hell due to the fact that you will have no usable power. if you want better gas mileage focus on opening up the intake and exhaust. Switch all fluids to synthetic and maybe even get a programmer.

 

[Tbars4]

you might also try the search button for " my quest for thirty"

 

[fernbeebe]

in the 60's we would change out chevy rears to try different rears with different gear boxes to test performance. One of the combinations we tried was a wide ratogearbox with 292 rear gears. The car would wind up forever but would cruise at highway speeds at really low rpms. Racing performace was nil but highway economy was teriffic. I am looking to get better highway gas milage because thats 90 percent of my driving. I would live with the crappy get up and go in and around for better highway milage.

 

[Tbars4]

you are a beebe??? where are you located...you might be a cousin, lol...:scratch:

i know some of the X's and explorer's came with i think 3.27's...great gas milage like you want but little tires...the next up size was 3.73's...and then 4.10's

 

[IZwack]

I think 2.92 is too low for such a heavy vehicle taking into consideration the engine onboard. Maybe if you had a torquey engine (stroker), then 2.92 would work. But also keep in mind that, as the ratio approaches 1:1, the transmission and the rest of the drivetrain is stressed more and more.

 

[Silver X]

I think the closest you could get to 2.92 for the 8.8 is a 3.08 gear. There are higher gears available too. Mustangs used to come with 2.73 gears to increase fuel mileage...but they had more end torque, lighter weight, smaller diameter tires, and low first gear to help overcome the poor rearend gear ratio.

As others have mentioned, your Explorer will be an absolute dog and you'll have to use more throttle to get it moving around town. Get a less restrictive exhaust and cold air intake, and reduce the friction in the powertrain/drivetrain. You could get new calibration programs to make it more efficient: lean out your fuel a little, quicken the shifts, etc.