For $1600 it sounds like
you went the replacement transmission route, after you had allready changed the torque converter. Hate to say it but I think you are barking at the wrong end. I could see something happening in the rear brakes, like a broken spring on the shoe that causes the brake to lock up in reverse only. I had a self adjusting cable snap on my 92 Explorer. The end loop lodged between the shoe and the drum. If you were going slow and gently put on the brakes, the rear wheel would lock up and squeel the tire. At higher speeds, everything was fine and there was never any noise. It's either something like this or they rebuilt your same transmission and put back in a defective one way clutch.