My father has an 07 400 that won't shift up or down in the electric shift mode. Does absolutely nothing. When I switched it to Auto to load on the truck...... it barly made it up the ramps. Lacking power and almost sputtering. When in reverse it acts like it is bouncing off the Rev limiter and barly backs up. Any help and or suggestions would be greatly appreciated.
Welcome to the forum. Step 1, download your service manual here, if you don't have a copy already:
Step 2 would be to take apart, one by one, clean, and re-connect with dielectric grease, every electrical connector. All it takes is one bad connection in the entire electrical circuit to make these hondamatics not function. Happened to mine once a couple years after I bought mine.
If no change after that, you'll want to see if it's throwing any diagnostic codes, which the service manual will guide you on.