Welcome! I see it is your 1st post.
You should take the time to set up your signature line with all your pertinent information in it.
Slide gear(s) and motor/gears can be replaced.
There have been past discussions on this and a search of the forum should bring up results.
Forest River has used several types of slides over the years.
Do you know what your is?
Schwintek slides have rails attached to the side of the slide out.
LCI (Lippert Industries) has several models that include through frame, above floor, etc.
There are gears and motor/gear kits available online here are two of the most common...
Lippert Components 191072 18:1 Venture Motor Replacement Gear Set
RV Slide Out Motor 18:1 Ratio Replacement Motor M-8910