Hey there! I have a 1976 280z and I had the U-joints on the outer ends of the halfshafts replaced a year and a half ago, and one day a few months ago, I was coming off of a huge on ramp into freeway traffic, and I was really gunning it. I heard a large clang and clunk from the rear. I thought it was a rock coming dislodged from a tire in the rear. Later on, I found out that the noise I heard was the U-joint basically exploding under the pressure/ centrifical force. I got it fixed though, so no worries, but I was amased after the fact how close I was to disaster. I can only imagine what kind of damage the halfshaft could do whirling around in the wheel well. BTW, I also had to replace my drive shaft because the U-joints (non-replacable) on those went bad. That was fun. Has anyone else destroyed U-joints on their Z?