Click
I dont have a solution for you but experienced the same symptoms when I had my '06. It was purchased new and the sound began a few months afterwards. Nobody could locate the issue. Even the "weird sound guru" at the dealer went for a ride and was baffled. When they had it up on the lift and in drive going through all the gears the sound never materialized. It was only when there was weight on the vehicle. This sound was the reason I sold it two years later. No way I was going to listen to that for the rest of the time I owned it.