Yep, just sounds like a maintenance issue. Would love to know what or if that dealer did anything to it last year. I'm assuming you regularly check the torque on the castellated nut and other mounting fasteners.
I have the Sidewinder (same principle but different design) and re-grease it once a year when I do my wheel bearings. Have had the best results with Lucas Red-n-Tacky grease.
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder