My single slide rides on two bottom rails. The rails are driven in or out by two gears operating in tandem that rotate and are geared to the bottoms of the rails.
About once a year, I lubricate and clean the rubber slide gaskets by saturating a small rag with silicone spray and wipe down the surfaces of the gaskets. This can be done fairly easily when the slide is about half way out.
About once a year, I clean the rails (when the slide is all the way out) with a rag wet with Naptha and then spray the rails with Blaster Garage Door Lubricant. This lubricant spray dries to a non-sticky slick film;
here's a link to that lubricant.
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There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2021 Chevy Duramax; Pullrite Superglide Hitch