Re: The whirring noise
It sounds like the carrier bearings in the rear differential are going bad. I had the same and had mine replaced at 72k, even though the diff fluid was changed at all 15k intervals. Since then I quit using Mopar gear oil (just repackaged Pennzoil crap) and only use Amsoil, which has much better spec's, and is cheaper than OEM. Mine was covered by extended warranty, otherwise would have cost $ 1,500. Make sure they file the area around the diff seal flat before installing or it will leak fluid. That also happened to mine, and they had to redo it again.
2006 GC Overland QD II
5.7 Hemi, Modern Muscle 85 mm CNC ported TB, Apexi super voltage stabilizer, Billet Tech. Catch Can, Koni FSD shocks/struts, SRT8 sway bars, Cooper Discoverer SRX 255/65/17, Amsoil fluids, Diablosport Intune CMR tuned by Hemifever tuning.