As is often the case the solution would not have been found in any of the aftermarket repair manuals and certainly not in the venerable shop manual.
I began to have strange card flapping noises coming out of the car. I feared that I’d have to pull the motor and go through it. Maybe I’d have to rebuild it.
Fortunately the problem was simple to fix and sadly it was of my own doing.
One recent winter when I had the trans axle out of the car I noticed that someone had trimmed a wedge of alloy bell housing material from the bottom, exposing the flywheel gear teeth.
It clearly was not part of the casting. There were grinder marks. Later I learned that the wedge shaped cut out was likely a factory alteration.
So I fashioned a nice cover for it and installed it.
Much later, for reasons unknown, that cover began to make contact with the flywheel. It has been removed and isn’t going back in.