Abstract: Employee #1 was driving home in a company truck, 2002 Ford, F250, 0.75-ton, when he heard a noise, which due to his mechanical training, experience, and knowledge recognized as a U-Joint going bad. He contacted his office and informed a supervisor of his intention to change the U-Joint himself because he had the skills and tools. While he was under the truck and as he was removing the last bolt, the drive train became free and the truck began to move down the driveway. The differential housing struck Employee #1, causing serious injuries that required hospitalization and surgery over a period of six days.