Whenever I hear about a grinding noise comming from the wheel area, I always gotta chime in about the CV joints. I realize your mechanic checked it out, and if you trust him good enough, then just ignore the rest of my post. The CV joints were the problem on my car, and after checking everything I was told to check on here, a friend of mine mentioned to check the CV boot. Sure enough, there was ahuge tear in it and all the lube was gone. Check the CV boots real good and look for any tears or lube on the outside of the boot. -Nick
