My first instinct was to just keep my mouth shut and let you find out for yourself instead of being the devils advocate, but it sounds like something is coming apart and jamming shift valves.
Possibly a planetary set or some other metal particles producing failure.
Could also be a sealing ring broken allowing fluid where it doesn't belong yet and binding it up, or one valve making the shift and another not letting go.
Very first thing would be to pull the pan and have a look at the contents.
