Transmission fault code P0732?

My truck overheated one day and about a week later the truck wouldn't shift out of 2nd gear and the O/D light started blinking with "Trans Fault" on the display. I hooked up a scanner and it gave the code "P0732" if I drive it really slow without letting it go past 2nd none of the lights come on, but as soon as I try to give it some gas and it gets to second gear the engine revs and the lights come back on. This truck just had a brand new transmission put in it about a year ago and all the fluid levels are correct, and the fluid doesn't look, or smell burnt.

I'm leaning towards it being something electrical and maybe the truck overheating somehow messed something up, or maybe it's irrelevant. I'm just not sure how exactly to go about locating the short or Fault. From visual inspection I haven't been able to locate anything but I know that doesn't mean the wires are good. I also replaced the output shaft speed sensor with no luck. Should I look into replacing the input sensor?

Any advice or help would be greatly appreciated! This is my work truck and I've been unable to work ever since it started acting up, kind of a double edge sword, don't have the money to pay a shop and can't work to get the money without my truck.