Technically the "flywheel" is known as a flexplate in automatics. The 3.3/3.8's have a timing chain - no belt. It's possible the flexplate has cracked jaggedly around the mounting holes allowing the flexplate to move back and forth and may have disrupted the timing enough it won't run. It's sort of a known issue the flexplate can develop cracks like that - my '00 T&C Ltd did this. The solution was to replace the flexplate at a cost of around $600 (mostly labor - the flexplate was only $67). At idle with the AC on mine had a sound like marbles being shaken in a coffee can. The clunk doesn't sound good and could be a clue.
I think there is a cover on the transmission that can be removed that allows some of the flexplate to be viewed.
I think there is a cover on the transmission that can be removed that allows some of the flexplate to be viewed.
