We had an interior wall piece break next to the slide where the fridge is on our 4150. Problem was defective workmanship on welds. A couple of places were tacked and not a complete bead laid. Also a piece of square tubing was hammered in place to make it fit with a couple pieces of wood placed underneath and screwed in. Dealer says faulty workmanship...out of warranty period, not covered by extended warranty due to being structural and no insurance coverage due to faulty workmanship. Keystone/Dutchmen answer, "customer caused" by something being trapped between slid-out and wall. Know reason or answer given to the weld breaks, square tubing or added wood and screws all on the outside. $3500 later, heading to small claims court. Good luck - the Dutchmen quality control and customer service are non-existent! Your only hope is that it is still under warranty.