If the slide is moving around in the opening, it may need to just be adjusted. On my previous coach, if I didn't use my threaded lock bar, the slide would move around enough right behind the driver's seat to be annoying. On y current coach, I had one occasion where the slide behind the driver was making noise, but it has auto locks.
Now, I make sure that when bringing in the slide, I hold the button down for a second longer to make sure the slide is tight. Next time you get the rattle, pull over, extend the slide a few inches and then bring it back in, holding down the retract switch an extra second after contact.
