I have an 06 5.4l if I put some 4.56 gears in it will I have to program the truck to accept the gears and perform the way they should??

 

Mechanically they will perform find, no electronics to worry about in their operation. You will however need a new PCM calibration to make the speedo read correctly. There's two ways to go about correcting the speedo: the dealer can do it just to adjust the PCM's figures usually about $80 OR buy a quality programmer (custom tunes are preferred) and you can adjust the ratios to make it read correctly and get a power gain.

 

I own a Diablo programmer so hopefully I can figure out how to do it on there