They could very well be the Lippert SBS or Sealed Bearing System. I HAD those on my 2010 CC and found three of four bearings were wearing beyond serviceability. The way to check is to jack the tire off the ground. Grab the tire at the 9 and 3 O'clock positions and try to wiggle the wheel in and out. If you find they feel sloppy, then call Lippert and have them send out two new axles with conventional hubs for FREE. That's what they have done for many owners and as of last year there was a recall on the SBS axles from what I understand. When I called Lippert, I aked for new bearings and they said they would do one better and ship out 2 new axles. All I had to do was swap over my backing plates with the brake hardware and connect up the wiring. Lippert has phased out the SBS system. Do a search, there have been lots of failures with some catastrophic. Good luck!
2010 Cedar Creek 5th Wheel 34SATS "The Beast"
2006 Ford F350 Lariat 6.0L Diesel
2003 Harley Heritage Softail "Hogzilla"
1988 Harley Softail Custom "The Fireman"
1986 Marriage to "Wifey" (patience of a saint)