Well, I just had the same problem again. This time while towing my trailer in very cool weather, around 60 degrees. It was fine for the first hour and a half towing on flat ground, After I got into the hills the OD slight started blinking again and the transmission was getting hot. Even on downhills and flat ground the temperature would climb. Only pulling over and shutting it off would cool it down. I ended up having to leave the trailer and come back with another truck to get it. The truck ran fine on the way home without a trailer. I just ran the codes and I'm getting 26 and 62. The book lists 26 as Vane Air Flow Sensor, Mass Air Flow Sensor, or Transmission Oil Temperature, So I guess its referring to the temperature. 62 says transaxle problem - 4/3 or 3/2 pressure switch circuit failed closed or converter clutch failure. Sounds like trackspeeder was right about the converter slipping.