I have a 2wd 2008 F150. When I turn, only when going fast, I hear a weird noise which kind of sounds like the wheels are rubbing, but they aren't. They're stock size. It does not happen at low speeds, it can get pretty bad on curvy roads that have high speed limits though. Once I hit about 30 mph, no matter how far I turn the wheel I can feel it happening and hear the little grinding noise. Nothing at low speeds. What's the deal?