Driveline vibration out of now where! Help!
Someone on here should be able to help you find a reasonable tranny man in your area that can help you out. So yeah just drop the trans pan and trans fluid, and see what is showing up for steel in the bottom of the pan, if there is lots of steel in there then it needs to come out.
See if you can find another Mopar Guy in your area that can assit you and help find that right guy to get the trans fixed. Can walk into the local tranny shops in your area and ask if anyone is familiar with rebuilding the mopar 727 trans then go from there. You can feel them out at the same time to see if this is someone you want to do business with, or maybe they are just a good sales man.
From everything we have gone over so far with the info you have supplied I would say that it is the Bad Panetary Gears.
Keep looking into it a little farther, there are more things to discover . . .
Check to make sure the Torque Converter to the crankshaft Flex Plate Bolts are tight too. That could make some odd noises too if they came loose. Probably have to pull the starter and the front trans dust shield/inspection to get in there properly. Just in case . . .