The driveshaft looked fine after the lift, it needed an inch of extension at most, but I didn't see it as being a problem. The tabs are still on the yokes of the 205 and the 9 inch, so that wasn't the problem. I'm sure I had the right u-joint size as well, and no u-joints were broken.
The truck did a 3 hour trip down 45 at 65-75 mph and drove just fine. It wasn't until I drove it a few days later that I had this problem.