If I was to guess, I would say that this is the torque converter overheating. If the fluid is black, engine oil in color, then it sounds like it's burned. If you made a bill of sale that you both signed, you may have a case in the small claims court, otherwise, hit a trany shop. Sorry I have nothing good to tell ya about this. I replaced my trany in my 98 Misty with a junk yard one for about $900. Was worth the money since I paid $600 for the car.
