I have a 2003 F150 with a 6" fabtech and 35's that I just purchased. I noticed the OD light flashes and stays on when driving, the truck goes into OD and shifts smooth with no hesitation, the truck has 3.55 gears, could this be due to the 35"s and stock gearing?

 

When the OD light flashes a code is stored in the PCM's memory. Without the code nobody knows what's wrong.

 

Thanks mark, I'll get the code checked, I have a feeling it's just a bad sensor