I had some real bad vibs coming from my drive line a while back. I determined with alot of info from my brother Mopartners that the cause was when I dropped the trans out, then reinstalled it there was some sorta binding going on in the motor/trans mounts. I loosed all the motor mounts and trans mount bolts, started it and shifted from P to 1 several times, performed many power braking applications, some were extremely agressive. I then torqued all the bolts down....vibs went away.

I've gone through all the wickets everyone has mention: dampner, convertor, bent pulley etc etc.....

You might give it a try. I never had vibs before this until I removed the trans to replace the ring gear on the convertor.

Also, someone on Moparts referred me to a factory diagnosis diagram the Mother Mopar created back in the day. It was money! You might look in the arhcves....this has been since 2008...I'll look myself..

good luck!