The plumbers left. Nice guys, good work, and I am glad they were able to come today snd not Monday. I guessed it right. It was the broken soil stack in the wall behind the dishwasher. Not the repair but a threaded connector that had rusted and me using the plunger finished it off. It would have fallen apart on it's own and we would have noticed the sewer gad smell when it did. If I don't plug the drain again their repair should out live me. $500. Make the call, write the check. I might have been able to fix it myself over the weekend and have no hair left on Monday morning. Time for a toddy.