U-Joint Question - Part 2
FWIW, I lost a driveshaft once because the pinion yoke had apparently spread a bit and the u-joint was able to hammer it more side-to-side. Went to billet pinion yokes after that.
I would see if the u-joints had any play while installed, rear on jack stands and in neutral. Just to make sure, remove the driveshaft to see if there are any tight or rough spots when you rotate the trans end and rear u-joint caps.
U-joints usually don't show visible external signs of impending failure.
Good time to check the pinion/driveshaft angles.