if i go from 3.55 to 4.10 will i be able to recalibrate the speedo with a superchip? or will i have to change the gear?

 

You have to do it by chip on 99 and up trucks. There is no VSS gear. Send your computer code to Mike T and he will tell you if he can work with it or not. My Superchip fixed my speedo.

Ian

 

I have a 99' Lariat, 4r70w and 9.75" rear end...and in the tail shaft of my tranny I DO have a gear in there to change, most dont but Ford made so many variations of everything you dont know until you break it down...my gear is on the drivers side and sits behind a sensor plug....

5.4