low speed vibration/hum when cold

[Max Gunner]

Hi Guys, 2003 3.0i, 65k miles, automatic. Just noticed a kind of hum or vibration, only at low speeds and only when the vehicle is cold. After a few minutes, there's no symptoms at all. It doesn't matter it it's in forward or reverse. Doesn't seem to be any problem steering, or any difference in the symptom whether going straight or turning. The best way I can describe it is like a giant cell phone on vibrate.

Any thoughts? What should I look at?

thanks,

MG