As soon as the temperature gets below freezing, sometimes when the truck shifts, it's like it pops into neutral and as long as I just let go of the throttle and press again it catches. Sometimes I will lose reverse and the indicator light just flashes. Happens in drive on occasion and the truck is dead in the water until I clear the codes then it's fine again for a while. Transmission was built about four years ago about 60k miles ago. A stage V PPE kit was put in. Am I looking at a total rebuild or the NBSU switch problem??