I got a code 37 on my truck. My book says its either a torque converter clutch or tranny temp. I havent seen the temp go too high, and I suspect the clutch. I have a DTT tranny controler installed and there is a switch on the dash that apparently controls the controler. I bought the truck with the setup, and dont quite understand the switch, I have a basic understanding of the controller operation, but with the switch in either direction, lights still come on on the controler. Overdrive and TC lockup come on in either direction.