I had a bad bearing and it was a constant hum.. kind of like an airplane.. it would go away when I veered left.. and louder when I veered right.. you should check and see if it goes away one way or not. I did not however have any wheel play.. what I did to diagnose side was jacked it up and spun the wheel.. you should be able to hear a little more noise. or you can put your hand on the strust tower when you spin the wheel.. you can feel helly vibrations.
-kev
