IDguy
Try this before going for 2nd gear.
Tow/haul on before starting down.
Before your ready to use the brakes firmly tap the brake pedal quickly two times. The transmission should shift down, if it doesn't, tap the brakes a little harder and quicker.
It would be good if you know a place along your route where you can practice your tow/haul/brake procedure, good luck let the motor home do the work.
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