[twindman]

I have had frame flex 3 times. Once with my 2006 Montana. The wall between the washer/dryer cubbard and the closet would bow out about 3 inches when on truck or on landing gear(I can't remember which). Welds right at the point where the frame goes up and then forward for the bed room.

Then on my current unit, the back wall was creeping back about 3 inches. Dealer 'fixed' it and I think they put in bolts/screws from the back wall into the side wall aluminum 2x4s. After about 2 more years, it started to slip again. I looked in there and the 2x4 had pretty much a hole about 3 inches in diameter from multiple screws being inserted, stripped out, and new ones inserted and stripped.
This time the took the lower side area off at the back and 2 or 3 2x4s were broken away from the bottom area, which I think caused the back wall to shift. Also, at this time the front had frame flex again and the took the front cap off and fixed it.
So in 16 years, i have had 2 frame flex in the front, back wall loose, and sidewall welds also broke off.
I HAVE been to Alaska twice and put on 130,000 miles in 16 years to 47 continental states tho, so that may have caused some of this.