I have recently started getting a bit of a hum from the front wheels when going around sharp turns. I don't notice it when going straight. I would describe the sound as a hum, similar to the sound you get from knobby tires on pavement. The sound is not constant, but only happens briefly once each time the tire makes a full rotation. Any ideas? It's a bone stock 2005 LS 4x4 with the 3.5.