Norm,
Suggest you call Monaco or BCS for info. My 07 has a (IMHO) lousy arm mount that depends on torquing the arm nut to get the copper sleeve in the arm to bite into the shallow splines on the drive shaft. Someone on the Forum recently came up with use of a star washer as a method of ensuring the arm didn't move except in sync with the shaft so maybe that is a solution if / once it strips.
Steve