Why is there a humming noise coming from our Ford Explorer?

There is a humming noise from a 2003 Ford Explorer. It's loudness depends on the speed at which your driving. We do not know if it coming from the wheels or the engine. What is the source of it?Why is there a humming noise coming from our Ford Explorer?Time to trade that guzzler in. Have until Labor Day.Why is there a humming noise coming from our Ford Explorer?usually the humming noise comes from a dug wheel well you should check if the tires are perfectly balanced...........or the noise comes from the engine section, or the propeller shaft, or if it comes very nearer to ur compartment the gear box for front side and differential for rear side........well with out check in it there could be no answer for it, you can basically first check from where the noise is coming front or back?? coming from left or right?? hoping some wheel bearing also makes noise if they r worn so as i said diagnostic is necessary...do it your self or Ford Motors Always there!!!Why is there a humming noise coming from our Ford Explorer?Could be any number of things. You should be able to tell if it's from your engine compartment though. I'm going to guess that it's your wheel bearings though. Either that or your power steering pump. Does it get louder when you turn? If so, then it's your power steering pump. It could also be your A/C clutch going out.Why is there a humming noise coming from our Ford Explorer?
A lot of knobby SUV tires will sing. And the sound will change as you go to different types/roughnesses of pavement. Even my car tires sing on certain bridges.