I have a '00 Glastron 195SX with a 5.0 Volvo, and managed to hit a rock on it's maiden voyage this spring. All that happened was a small ding on the prop. Now 10 trips on the lake later,I am starting to here a noise coming from the lower unit. Could this be coming from the prop or something more serious? Everything checks out OK as far as clean oil in the lower unit and prop moves freely with out any noticable noise and feels solid. Please advise.