Rhythmic humming noise from drivetrain
 

My '08 4.8 sport has a very low volume (radio off) rhythmic humming noise heard inside the cabin which repeats every second or so at highway speeds. It's almost like a harmonic vibration noise you hear when the tires go over certain surfaces, but it is constant as long as I'm going over 55 MPH. I think I can feel a buzzing vibration through the gas pedal and maybe the steering wheel, but it might just be my imagination.

I first thought it was part of the noisy runflats, but the noise persisted after replacing them with Conti DWS tires. I'm replacing those tires with Michelin Latitudes (that's another long story) in a week or two but I don't think the noise is from the tires.

Does anyone else notice this noise in their car?

I have a similar noise on my 07 4.8i in the front driver side wheel well area. Sometimes on certian roads I will have a humming, vibration in the center dash.