I am looking in to a used Jeep grand cherokee. it has the quadrdrive system. when driving it dose ok but on turns there is a sorta of grinding noise. and if you turn sharp the wheel hops. ( like if your in 4 low and trying to turn on pavement ) what could this be? it has all time 4 wheel drive, Netural and 4 low. ( oh and when driving you here this mettle on mettle rubbing noise. If you can imagine how a train wheel sounds when it runs on the train tracks, minus the noise of the loud engine and other distracting noises.