Overfilled Trans

The dealer overfilled trans when doing the 30K maintenance on a 2003 4cyl wagon. Now hearing high-pitched noise, particularly in overdrive (automatic). What damage would be caused by the overfill? How big a repair is this? And of course dealer is trying to say he didn't overfill!!!

Thanks,
Drew

I see you have had 20 people look at your posting, with no reply. Here's my advice, call AAMCO