We had an RV that acted similarly. I dropped the bottom so I could get to the motor and gearing. Turns out the gears were plastic! We went through several plastic gears until I could find some metal ones that worked.
I never found any videos for my particular RV, but you never know what a Google search will turn up
Also, it might be worth it to get an estimate from an independent RV service only shop. Could be a lot less than you think.
Good luck and let us know how it turns out.
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder