I WAS DRIVING MY 2011 GMC ON A HIGHWAY IN MASSACHUSETTS WHEN THE TRANSMISSION DECIDED TO FAIL. MY REAR WHEELS LOCKED UP AND WAS CAUSED TO TURN SIDEWAYS ON A HIGHWAY. MY TRUCK WAS HIT BY FOUR OTHER VECHICLES. WELL THE TRUCK GOT FIXED. THE TRANSMISSION WAS REPLACED 3 TIMES! WITH ALL THE SAME FAILURES. GM NEEDS TO CHECK INTO THERE TRANSMITTIONS BEFORE IT COULD KILL SOMEONE. 3 TIMES ITS BEEN REPLACED AND ALL 3 TIMES MY REAR WHEELS HAVE LOCKED UP. WHY? YOU GUYS NEED TO FIX THIS ISSUE...