Well, I went to drain the rest of the fluid left after finding a leak, and I drained 2 quarts out, WTF. It had somewhat of a metallic look in the sunlight, but there was no noticeable granular feel or anything.

SO, I put 2 quarts of fresh fluid in and still have the same tranny whine. Don't know how to describe it other than maybe like the sound of the differential scraping the case of the transmission every revolution. Or one of the cone bearing on the diff seized up, I don't know.

What is that access panel on the drive side of the tranny for? Anything worth trying before I pull it out and take it to a shop? All gears work and shift smooth as butter. All that is present is an annoying noise under any bit of acceleration in any gear (more prominent in 2nd-5th).