Following Dmax and John Kennedy's advice about not towing up a grade in overdrive following a 737 fault code, I again pulled the loaded 10K trailer (plus 60 gal aux fuel, 80 gallons of water and a Honda generator) 1000 miles round trip to Talladega, AL with no problems, until I tried to back the trailer in the driveway at home and got a "range shift inhibited" message. Two or three key cycles cured it with no codes. A month later I was just driving down the road normally without the trailer and my check engine light came on, but the truck functioned normally. When I got home I checked with my OBDII and it showed a 700 fault code. Knowing that my OBDII couldn't read the specific code I assumed it was just a repeat of the original 735 code and I cleared the code. Now today I was backing into a parking place and once more got the "range shift inhibited" message, but no fault code. Two or three key cycles cured the problem. The truck drives and shifts just fine with no codes.

The real question is do I have some problems serious enough to have to rebuild or replace the transmission ???