Lubed the slide mechanism and all the rubber seals for the slide-out. The slide is working good now and drive motor is not stopping and clicking during extend process. Only at the end of travel, each way. No gears or motor replacement needed. Thanks to you all for your info and recommendations.
There is a vibration rattling either during extend and retract operation, sometimes. I don't know. I may have to open up the under-belly material to observe the slide mechanism during operation if it continues.

The Previous Owner had used this RV to live in during the build of their house, so the slide-out had been extended out the whole time. When I went through cleaning and conditioning the rubber seals, I noticed the rubber seals are almost flat instead of round. It seems to me that the rubber seals should be round. What do y'all think about that?

I, also, noticed once the slide-out was retracted all the way in, the forward section underneath had about 3/8" gap between the chassis rubber seal and the slide metal frame. It seems to me that the rubber seal should be making contact with the metal for a weather-tight seal. Attached is a picture.




Does it look like the rubber just needs to be replaced (the rear chassis rubber seals against the slide metal frame); or, does the forward slide mechanism need to be adjusted to make this seal?
Also, the slide exterior siding front, bottom section, does not rest completely flush to the exterior wall of the trailer.I did not take a measurement, but, it's about the same distance as the picture above.
During slide operation, I notice the front section does seem to lag behind the rear section, a little. The drive motor is attached to the rear slide section and the front is engaged by the bar connection between the front and rear sections.