All you have to do is call AirXcel and they should send you a replacement Gear Box assembly. I have gotten several of them at no charge when ours bit the dust. They know there is a problem with the cheap design, but it's cheaper for them to supply replacements than to fix the problem.
Michelle & Ann
2018 Chevy 3500HD Crew Cab High Country DRW, D/A, 2016 RW39MB, Dual ACs, Auto Level, Auto Sat Dish, Stack W/D, King Sleep #, 17.5" Sailuns w/Disc, MORryde IS & Pin, Comfort Ride Hitch, 5.5 Onan, Res Fridge & Induction Cook Top