Lippert Slide Out - what is happening??

[Adony]

I have a 2010 Wildwood TT that has a Lippert in frame electric slide out installed. The slide out contains the kitchen (less refrigerator) and 2 lounge chairs. It extends 18" out when extended and is 13 ft wide. When the trailer was new, and I retracted the slide out, it would come almost all of the way in and about the last 2 inches or the inside edge would elevate slightly to insure the outside seal. When extending it, the inside edge would remain slightly elevated until it had traveled about 2 inches out, then the slide would drop down and fully extend normally. LATELY.. the slide would retract normally as before, BUT when extending the slide, the inner edge would elevate as before, about 1 inch out it would drop and scrape something / hesitate and then re elevate for another inch or so before leveling and fully extending. Hope you can understand what I am trying to say, but I am at a loss on this one.. Help or Ideas??