Just purchased a 2009 Winnebago Vista 32-K and we really like it. The only issue with the coach is that the two slides seem to really labor to open and close. They're "jerky" and at times the dining slide fails to open or close completely. Is there a way for me to lubricate the slide rails, and if so, with what? Thanks in advance for any advice you folks might offer! (oh, yes, always level and engine running).