If you are ever going to be near Elk City, OK--there is a DRV dealer, RollingRetreats, that has fixed these systems for several owners. Have heard the fix lasts very well after they have worked on it. Alignment/correct motors usually are needed.
Hope you get it solved.
Our current '15 has the cable system and rollers; our previous '05 slid on teflon blocks.
'16 40QBH Phaeton
'15 38RSSA Mobile Suites--traded
'05 36TK3 Mobile Suites--retired but not forgotten