Rather than pulling the tranny which would mean taking it apart blind take the car to a tranny shop & have them drive the car... As mentioned it could be fliud bypassing the pressure regulator causing a resonating buzz/whine... It could be the front pump or it could be the convertor... A guy that has done trannies for a living should be able to pinpoint the noise & & if it's the pressure regulator the trans stays in the car....

"The Armies of our ancestors were lucky, in that they were not trailed by a second army of pencil pushers."