That might not be the correct description of the sound. It is like having a flat spot on one tire. I jacked up the rear end so both drives were off the ground. Sure enough the rear right tire seems to have a flat spot/depression in it. In 1st gear idle, I held a straight edge to the tire and it was very noticeable. When I did the same test in all other gears, there was a very loud "knock"? that increased in frequency with wheel speed. The "knock" seems to be what I can hear/feel going down the road. More like a subtle vibration.
Any idea's before she goes back to the dealer?
The car has never hit anything or driven on anything other than pavement.
Thanks,
Rick

 

If there is a flat spot on a tire I know how to fix it, hahahaha. Just clean off the tires with a nice healthy donut or two (or three or four). The more round you get the donuts the better your tires will look. If it is not in the tires then it is probably something in the rear differential.

 

actually, it sounds to me like one of your rear wheels is loose, as in, the lugs arent screwed in all the way because that the exact noise it makes when your dealing with a loose wheel. just jack up the car and check to be sure.

 

Checked for loose wheels while in the air. Checked torque while on ground, everything checks out.

 

I have had this happen to me before, and sure enough it was just the guy I had tied up in the trunk!

 

my girl friend showed me some of her "toys" the other day...I think you just need to turn yours off and the "vibration and noise" in your rear will cease.