my freind has a 99 f 150 and he changed his gears from 3:08 to 3:73 s and also has low profile tires on 18 inch wheels and we cant get an honest answer from anybody on how to get the speedo back to where it belongs, he bought a diablo chip and they told him that it would fix his problem with the speedo but it doesnt. in that transmission can he change the speedometer gear or is it a electrical item that is needed for that year of truck. i would really appreciate some feedback on this because its driving me and my freind nuts at the same time

 

Sounds as though you are going to need to take it in to the dealer, and have them reprogram it. You can't just change the gear in the 99 and new f 150's. Hope this helps.

 

Welcome to F150online. The dealer can recalibrate it for factory tire/gear combinations only. The Superchip can be calibrated for a myriad of combinations. Get the exact tire height and the gear ratio and call Mike Troyer (his info can be found in the computer chip section). You can also ask him about the Diablo chip programmabilty.