Yes a little more info can Be helpful. Because a AT convertor Will do what Your saying I know BEEN THERE had That Happen. Also Is Their any Type Of Rattle at start Up Or Shut Down??? If So this could also Be a Lose FlyWheel Issue.
More info Please But hope all This helps so far For things to be testing/Looking first.}[oooooo]
Ps What do you have for a Dampener?????