do converters internally fall apart

[crm318]

i have been having a high pitched clattering coming from my torque converter/flywheel area. it happens on acceloration only. i thought that the flywheel might be cracked or a bolt loose. i checked it and it was all good however, i had a friend bump the starter while i was under the truck and i noticed that the sound went on a split second after the flywheel stopped. im assuming that it came out of the conveter. could a part be bouncing around in the conveter? is sounds like a hand full of pennies in a dryer when it happens and it only happens on startup and acceloration.