I have a 03 f150 4.6l v8 and i have a 6-inch lift on 35's my mpg is pretty crappy i dont know anything about regearing but i read some people saying it would help get your gas mileage back, would it be worth regearing, and how much would it cost? thx

 

im guessing its 4x4?

 

no 2wheel drive

 

yeah yu should regear. You can do it for under 500 since your 2wd

 

Changing your gears to a lower gear ratio (numerically higher) will deliver better power to your wheels. But your "mileage", especially at freeway speeds, will suffer. I'm guessing that with a lift & 35" tires, your main concern is not MPG. Now that your truck is looking good with the lift & tires, let's get more power to the wheels and get it moving a little better.

A lot of guys like 4.56 gears because they deliver more power to the wheels. But you have to consider "cruising" at or about 3000 RPM just to maintain freeway speeds and return 12 MPG.... Don't quote me at 3000 RPM & 12 MPG, since that is not an exact scientific figure. If you search, there is a chart somewhere with RPM, gear ratios, and tire sizes.

I'm running 4.10 gears with my 35" tires. This puts me just about where the truck was with stock tires & stock 3.55 gears. I'm still able to cruise at 55 MPH (1750 RPM), and return with 19-20 MPG.

Yes, you should regear. With bigger tires, you need new gears. But don't expect the re-gear to gain better gas mileage.

 

Just buy these gears:

Ford Racing 4.10 Gears (8.8in Rear)


Item #: 24002

Manufacturer Info: Ford Racing M-4209-G410A
Market Price: $189.99 - You Save 11% ($20.00)
Our price: $169.99
Availability: Usually ships the next business day.

OR

Summit Racing 14-0069 - Summit Racing® Ring and Pinion Gear and Installation Kit Pro Packs





large/multiple images $479.70

 

Then watch this video:

Rear Differential Gear Swap on Ford F-150

 

Don't do 4.10's. That won't even get out back to stock. You should go witg 4.56.

 

4.56 would be ok but the preferred gears would be 4.88's with the tires the Op is running

 

Nice video

 

i had the exact same combo as you on my 98...315s on 16"wheels, 2wd, 4.6. i had 4.30 gears installed and the truck drove perfectly since i did mostly freeway driving. id go with that combo again if i didnt have a 4x4 with a 5.4 since they dont make 4.30s for my axle.