Swissy,
You should start your own thread. This one is 4 years old. An automatic trans doesnt have a flywheel. It has a flex plate. rare but they can crack. You can take the bell house cover off and look at it especially where all the bolt attache to torque convertor.
What car do you have? I would look at motor and trans mounts and subframe mounts first. Also maybe need a tune up?