Did you check the joint to make sure it was completely loose (not binding) before you put it in? Sometimes they will bind a bit if the needle bearings can't move freely. A driveshaft guy showed me how to tap the shoulders of the yoke (and the corresponding places on the driveshaft) with a hammer (not too hard, just hard enough to smash your thumb about halfway
) a couple of times to free up the bearings before you install the shaft.