My 2006 6.0L F250 has issues only when I tow my 4500lb trailer in cruise control, the small wrench appears in my odometer screen, when i pull over and do a quick check, no leaks, no holes or anything. I start it up, it goes away and as long as i am not in cruise control, it does fine. Does anyone know what could possibly be causing this? how much do you think it could cost to repair?