If this is a through frame, electric slide, with rack and pinion equalizer mechanism , I recently had a similar problem.
The "shaft" connecting the gear/pinion clusters had a break at the midpoint weld allowing shaft to bow and make noise as it hit frame.
Lippert has a video on their site that shows how to remove and lube gear clusters, replace, and also how to readjust slide so it nests properly at seals.
It's not really as daunting a task as one might think. Simple hand tools a tape measure, and some drying silicone lube. Might need an extra person to help push the corner of the slide in against seal when equalizer is disconnected.
FWIW a rack and pinion equalizer mechanism CAN be used on electric or hydraulic slides as the equalizer is independent of the actuator mechanism unless ir has a center actuator motor integrated into the equalizer.
Mine just has a single screw linear actuator on one end and the rack and pinion equalizer works all on its own.
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2018 Flagstaff Micro Lite 25BDS
2004 Nissan Titan