My E36 ('93 325i) has the famous "Transmission Control Module" light on in the dash. It turns on just whenever it feels like it and drops into 3rd gear when I'm driving. I got it checked for codes and was told there are several possibilities but that it's most likely a short in the wiring somewhere between the transmission and computer. Has anyone else ever had this problem, or does anyone know where the short could be at? Any help or ideas are much appreciated!