The Crossroads/Redwood Service Center or the Redwood Factory may be the best choice. A friend of ours was having a problem with a slide on their Montana. Keystone/Montana Factory determined the actual opening for the slide was undersized. They removed the entire slide, enlarged the opening and reinstalled the slide. Been working fine ever since. Overall repair was something most Dealers would not be equiped to handle.
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