I have a 92 4runner with a front- end noise I can't figure out. It's between 15-20 MPH. I took the covers off of the locking hubs so that the axles are not turning, and the noise is still there. It's a thump-thump-thump that can be felt through the chassis/steering wheel. It's not brakes because I get the sound whether the brakes are on or off, and there is no pedal "thump" Can the hubs go bad and make noise even when not in 4WD? Also, what size socket do I need to get to the hub?