OK, I thought of something to try today. I'll try to get some tubing down
to the point where I can't get past with the snake. I'm not sure if that
point is the clog or a fitting. Anyway, from there I can apply hot water
down the tube and see if I can blast away with hot water pressure. If that
doesn't work, I can pump all the water out to that point and perhaps try
adding vinegar or perhaps other chemicals. At least a better concentration
would get nearer to problem with less dilution. I just wish the thing would
have been made accessible without tearing out.

Any other ideas?

Thanks!

RogerN