When you say "3x3", what do you mean? And it could be the gear in the tranny going bad. But when you do a genuine tranny flush you should have in total 10qts of fluid you go through. 1 of those quarts can be re-used for the .1 part and obviously the other 9 are for the 3. You drain, refill, drive, drain, refill, repeat. You want to do it 3 times because it flushes everything out fully. The first one I did the fluid was still dark so I did 2 more and now its red again. But for the whining I would suspect the gear could be going out. Is it just when you go into reverse or when you're in reverse and backing up. If backing up that noise is normal if you're going "faster" than normal, like 15, 20mph