If this problem is new after 3 years of success, you may have a damaged skid under the slide or a screw head that was worked out. A buddy had a screw break loose on his '04 Endeavor after several years and it messed up the floor. However, in fixing the loose screw he discovered that the slide floor had been getting wet for years and was rotting away (why the screw popped up). That "loose screw" ended up being a $7000 repair. Then we found the new floor was damp too, so we hunted and finally isolated it to a small leak in a window frame.
Former owner of 2004 American Tradition
Home is in the Ocala Nat'l Forest near Ocala, FL