An employee was trying to remove cylinders that open/shut the grappler on a boom loader. The employee removed bolts and pins holding the cylinder in place, but the cylinder was stuck. As the employee tried to manually remove it, the swivel moved and caused the employee's fingers to get caught between the swivel and a valve. The employee's left-hand middle and ring fingers were crushed. The middle finger was surgically amputated and the ring finger also required surgery.