check your wheel bearing
Have you checked your transmission fluid? Try that Cindy
wheel bearing
Check your fuel pump
Unplug it.
The differintial is starting to wear...
possibly your running RCAs on the same side as your power cable
Possible wheel bearing going bad.
I believe it to be the airbag (passenger) making that humming sound
bad wheel bearings will do that, usually in the front.
Same reason as the first expedition, and other similar expeditions: in the expectation of making money.
need to get your wheel bearings checked
Bad bearing?