Bump for my post, but additional info as well. Driving yesterday, and being hyper attentive, I noticed that at the same time as I hear the hum I can also feel a slight vibration through the floorboards. The condition causing this hasent changed, I just noticed the similtaneous vibration. Again it's not bad, barely noticable, but it's there.
Mods: Thule Xsporter 422XT bed rack, Underrail Rhinolining, MOPAR class IV Hitch, DIY CAI, Aero Turbine 3030.
Future Mods/Wishlist: Tuner, Daystar Comfort Ride 1.5" Leveling kit, Nerf Bars, Police style push bumper with light guards, KC or Thule trail lights, HID projector lights.