I have a 91 Silverado 2500, and in the rpos it has the code
MT1: Transmission - 4 Speed Auto W/Elect Controls H.D. (Hydra - Matic 4L80 - E).
I also have a 99 Silverado 1500 that I will be putting this engine in, some time in the very near future. Does anyone know if the older tranny will work in the newer truck with the wiring conversion?