WAS DRIVING ON INTERSTATE. GOING ABOUT 60 MPH STEERING WHEEL LOCKED UP AND BEGAN TO SHAKE AGGRESSIVELY. HAD NO CONTROL OF VEHICLE. HAD TO APPLY BRAKES AND GET IT DOWN TO 40 MPH BEFORE STEERING WILL UNLOCK. VEHICLE NOW IN JEEP DEALERSHIP WITH NO RESOLUTION. IN ADDITION I'VE HAD SHOOTING PAIN DON BACK FROM AGGRESSIVE SHAKING.