This is kind of a long story but bear with me. 98 Jetta TDI owner here.
The car starts making noise with a slight vibration. A intermittent grinding sound. So I drive it until it fails. And it did fail, or so I though thats what it was. My car still has the original axles so I have the big vibration dampener on the right front. It broke loose. So I cut it off and think that problem is solved. Car still makes the same noise with slight vibration. So I replace the right front wheel bearing. Now the noise is gone so that was definitely the source of that. Now, I still have slight vibration. It only happens under certain throttle conditions and it's different every time. Here are my ideas:
1. Right front drive shaft out of balance.
2. Motor mount gone bad.
3. Out of balance tire. Noticed the left front tire doesn't have a weight on it. But I wasn't sure that it ever had one.