Stripped 727 Transmission cooling line

Not sure I am following. Are you talking about the pressure line, the front most line? Was the line connected to the brass adapter when this occurred? Or was it loose and just banging around the tapped transmission hole?

If it was loose, could just be the first few threads on the fitting are buggered. If this is the case run a bottoming tap into the female fitting and replace the brass fitting. If it is truly stripped out, carefully stuff a cloth patch into the port and tap the hole for a larger hole (you will need to buy another brass flare fitting). After it is tapped, use a pair of long tweezers and pull the patch back out. I'm not sure where the pressure port goes or if you can get to it from inside.