I am a new user and figured I would ask this question before I went down to the dealer. I have a 2008 Dual Cab 4x4 Long bed with automatic transmission and 4.0. I purchased used and currently have about 20k mikes.
Anyways, I have a hum...probably more of a vibration that occurs only during acceleration and only at highway speeds. It seems to occur around 2100 rpm and will disappear when I shift to 4th and the RPM increases. It will also disappear if I continue to accelerate in 5th and the rpm increases above 2400-2500rpm.
I could happen at other times, but I really notice it under the above conditions.
Like the Truck, but it is really annoying as I spend most of my time at these conditions.