I think you are screwed. I had this happen on a Pontiac wagon years ago, tube that is in radiator fell off and it sucked water into the transmission. I kept changing the fluid and finally got it to be red again, but a short time later the transmission would not move in any gear.

You could try flushing it and see what happens. All it will cost you is some transmission fluid and time. There is that one chance that you caught it before any damage occurred and at least you can say you tried to save it.

Don