An employee was under a truck using an impact wrench to remove the first of two bolts located on the carrier bearing of a driveline. When he removed the first bolt, he noticed the second bolt was stripped, but still needed to be removed to successfully remove the entire driveline. As he tried to remove the second bolt, the driveline shifted toward him in a downward motion, causing him to react and catch the driveline with both his hands and feet. He then asked a coworker to help remove the second bolt. Once his coworker removed the nut and bolt, the driveline became loose and fell on his right elbow, smashing it to the concrete and causing a fracture.