C/K TRUCK Current tools do not have a large enough opening to accept the ball joint of the GMT800. Using a hammer to remove the ball joint can cause damage to the ball joint and related components. This tool applies extreme pressure on the ball joint stud to break it loose. Loosen the ball joint nut. Install the tool on the ball joint and pop it loose by turning the forcing screw. Also used as a wheel stud remover on certain vehicles per a September 1999 GM service bulletin.