I just went through that with the front right. Thought it was a bearing cause was getting some rumbling. Posted it here and talked to a few others and they virtually all said shouldn't be the bearing for the age and parts supplier said he'd never heard of one on a D4 go.
Long story short I replaced all four rotors and pads and the noise reduced significantly after that so maybe brake related noise. Noticed inside tire wear and I think im just hearing tire noise. Camber on the wheels seems a bit extreme for a 4x4 and I DEFINITELY need a wheel alignment. Noise all but disappears when I turn the wheel and is worse on certain road surfaces.
Not sure if that eases your mind about road noise. :lol2:

