[old cool]

Please don't leave us hanging if you solve problem. Some thoughts for consideration are drum and wheel weight distribution and I'm not referring to wheel weights for balancing a tire. One of my wheel studs had a yellow dab of paint on it. I read somewhere that this old school marking was for positioning the wheel based on the valve stem opening. Don't laugh, not my idea.
Also, worn slip yokes may affect spin of drive shaft. Im going to look at mine when weather warms. I see recommendation for packing yokes with grease to help clunking (temporary fix). Just wondering if this would also affect smoothness of driveline???
Good luck and don't forget to update.