The HD truck is making a noise, which sounds like its coming from the left front that I thought i knew for sure what it was.... its a slight grinding upon every rotation of the wheel when the wheel gets to that point... I thought at first it might be a rotor or the bearings... Well, i thought i could rule out rotor, b/c i can't feel anything at all in the brake pedal... So today, i was going to tear it off and replace bearings, but when i got the truck up in the air and spun the wheel, there's no noise.... Both front wheels spin freely with only the normal little bit of noise from the brake pads contacting the rotor....

Any thoughts on what else i could look for?

I figured if it was the bearings, it would make that noise free-spinnign in the air as well?