EXPERIENCED EXTREME AND UNCONTROLLABLE VIBRATION IN THE STEERING WHEEL AND THROUGHOUT THE ENTIRE TRUCK (DEATH WOBBLE). THIS HAPPEN TWICE ON THE SAME DAY, 14 JANUARY 2018. THE FIRST OCCURRENCE WAS AT 70 MPH AND IT DID NOT STOP UNTIL THE VEHICLE SLOWED TO 50 MPH. THE SECOND OCCURRENCE WAS AT 60 MPH AND DID NOT STOP UNTIL THE VEHICLE SLOWED TO 45 MPH. APPLYING THE BRAKES MADE IT WORSE. THE VIBRATIONS WERE SO INTENSE IT PULLED A MUSCLE IN MY NECK. BOTH OCCURRENCES WERE RIGHT AFTER HITTING A BUMP IN THE ROAD.