How can I know what gears came in my 2wd 2004 F150 XLT 5.4l 3v? I just bought an Edge Evo tuner and need to know some things to set it up properly. I'm looking to setup the towing performance tune and correct my speedo. I had 17" factory crap-chrome wheels and just put on 18" FX4 wheels with Goodyear A/Ts. I setup the Edge for the tire size but my speedo is 3-4mph too fast, before the edge it was 3-4 mph to slow. I set it up for 3.73 gears but now sure if I have the 3.55s instead. I also need to know what I need to set the rev limit at and the WOT shift points. I've tried searching but I'm not having very much luck. Any help would be appreciated.

 

Look on the door sticker for the axle code. It is a to character code. If a letter and a number, it is a limited slip. If it ends in 6, it is 3.73. If it ends in 9, it is 3.55.

 

Thanks! The axle code is B6 so it's a limited slip 3.73. Now why is it that I set for the correct tire size and gear but my speedo is off?

 

Can you provide the old tire size and the new tire size?

 

Original tires: Continental Contitrac: 255-65-17
New tires: Goodyear Wrangler A/T 275-65-18

 

There's your issue right there.

The Continentals are 30.05" in diameter.
The Goodyears are 32.07" in diameter.

That's a 7% difference in tire size, so your speed will be off. Make sure to adjust your speedometer setting up by 6.3%.

 

http://www.1010tires.com/TireSizeCalculator.asp

 

I've set it up for the FX4 tire size already which should be the 7% difference maybe? I do know that different manufactures have different actual sizes even though they may print a 217/65/18 on the outside.