I would suggest that you THOROUGHLY re inspect the front flex disk. As engatwork said, the bolt holes wallow out. You have to wiggle it around a good bit when underneath to determine the condition of the flex disk. Mine ALMOST went undetected when I was looking for my problem. I had to shake around a good bit to find it.

The front disk will go long before the rear because it is exposed to the engine and catalytic converter heat.

Good luck,