When one of mine started skipping it turned out to be the thrust bearing immediately under the top cap that transfers the force from the leg to the frame of the trailer.
I have a dual motor Atwood system and since the trailer was in the driveway we tore the passenger's leg down on the bench and replaced all of the bearings and gears. (The Atwood kit is about $30 per leg. Don't know about yours.)
If you have to do a replacement anyway, you will probably be much happier with a dual motor system. More power and much easier to tweak the side to side level.
