I just returned from a wonderful 5,000-mile trip out west in a 2007 Holiday Rambler Endeavor, with just under 30,000 miles on Roadmaster chassis. I had observed minor edge feathering on the front tires indicating an alignment issue but nothing major.
About 500 miles from getting home, noticed some minor shimmy in steering wheel and observed minor cupping on right front tire. After getting home and unloaded, took motorhome to get routine service done, including oil change, filters, and chassis lube. After getting chassis lube done and heading to Cummins shop 7 miles away, the minor shimmy became severe! At slow speed, nothing detectible but once getting up to 45 MPH, steering wheel suddenly wabbled severely until I dropped speed back down to 35 or so. Then after gradually returning to 45, all was fine until I hit a dip in road, and the severe shimmy started all over again.
A quick look under unit showed no visible sign of broken shock mount or steering linkage issue. Cummins looked it over but are not chassis people.
I now have it in a local truck service garage (no HR or Monaco dealer in area) but it may be a few days before they get someone on it.
Any thoughts on possible causes or things to be looking for? The Roadmaster chassis is not part of the recall with rear trailing arms.