Anyone had these symptoms with a 904?

Well if you do that, it would be nice to know what ails this one.
But before you rip it out, I would do either an oil pressure test if you have gauges, or at least an air-pressure test.
IIRC you can transfer valve bodies between 67 up to something like 73/74 Or the PT KD item can also be swapped onto older VBs.
Too high a fluid level can do strange things too.
The whine is probably a planetary; but don't know about the sudden-onset.