The drive mechanism is not the only thing to clean and lubricate on a slide. The rubber seals that brush against the sides, top & bottom can also get dirty or maybe even salt-encrusted if you are on an ocean beach. Same for the exposed underside of the slide, which has to ride up and over the edge (and probably the interior carpets as well) when the slide retracts. All of these things contribute to friction and slow moving slides. Simple cleaning is usually sufficient, but some folks use a "slide out lubricant" (usually a pure silicone lubricant spray) on the seals, which is supposed to preserve them as well as providing smoother operation. Don't put it on the underside itself, though, or you may spread it onto the carpets. Be parsimonious - excess lubricant collects dirt and then spreads it around.
One dealer recommended that I use a slushy solution of dish detergent & water to clean and lube the slide seals. It is an excellent degreaser and a decent lubricant that won't harm the rubber or carpets. Makes sense, but I don't know how long it clings or retains its lubricant qualities. But he used it on our balky slide and it then worked smooth as silk for the next several weeks. Then our factory techs simply waxed the underside and got pretty much the same effect.
