What type of slide? I have seen a lot of complaints on Thor units. Mine does the same thing. Sounds like 2 ballons rubbing together. I have had it in the shop, lubed etc, still does it. talked to some folks with a Palazzo with the same issue who had a factory rep come out and can't figure it out. I would love to find an answer to this one. I have tried a slide lock and it does not help so I don't think it's the seals, at least the exterior ones. My bet is something rubbing on the inner workings. lube will not fix the issue.