904 Downshift Squall or Howl

I've run into something like that on a few/several higher mileage 904s, which I attributed to the planetaries. I ran them like that for years,and years. Your results may vary. It was more of a whine tho than a howl.And the pitch and the volume changed with each downshift and with the driveshaft speed.
My GV is dead silent, under all circumstances. I cannot even tell it's there.