If the camper is left outside the moisture builds in around the lower bearing on the electric motor. That is the most likely place for the bind grind you hear. Because the white housings on each motor does allow a minute amount of moisture build and the bottom bearing nestled in an undrainable metal lobe housing, the moisture builds right there and rusts that bearing.
My jacks outside 15 yrs in PNW rain are still functioning because each year I cover the jack heads with a freezer bag for winter lay up. Part of my winterizing includes removing the electric motor cover (slides down off the motor with 25 psi air nozzle) and spray oil into the lower bearing. Use excess oil sprayed to wipe down elect motor housing and put cover back on. Good to go for storage with freezer bags for covers.