strange resonating vibration

[beatshack]

hi, i have a question for anyone who has had this same problem, or may know what the symptom is caused by. I have a 94 talon ES with auto tranny. around 3500 rpm and again at 6500 rpm i am getting some strange resonance-type vibration, in every gear, but most noticable in 1st. I am trying to figure out if its something loose in the driveline itself, or if it might be something else loose.. anyone heard of this problem before? its very annoying to drive with. thanks in advance for insight.

 

[rollingrust]

Balance shaft out of phase?

 

[beatshack]

you could be right.. i rev to 3500 and 6000 in neutral, and its smooth as butter.. only happens in gear/under load.

anyone else?