WITHIN MINUTES OF DRIVING MY SON TO SCHOOL, I HEARD A GRINDING SOUND FROM UNDERNEATH MY CAYENNE, THEN A SQUEALING, AND THE CAR BEGAN TO VIBRATE VIOLENTLY DURING ACCELERATION. THIS HAPPENED VERY QUICKLY AND WAS FRIGHTENING BECAUSE I WAS CROSSING A BRIDGE IN MORNING TRAFFIC. THE SERVICE MAN AT THE PORSCHE DEALERSHIP TOLD ME THAT THIS IS AN ONGOING PROBLEM WITH THESE VEHICLES AND THAT MY DRIVE SHAFT HAD COME APART. I AM A VERY CAREFUL DRIVER AND MY CAR HAS LOW MILES. I BELIEVE THAT THERE SHOULD BE A RECALL AND THIS IS SAFETY ISSUE BECAUSE OF HOW QUICKLY THIS HAPPENED WHILE DRIVING. *TR