Following my first post yesterday, I think the diagnostic could change because stupidly I didn't mentioned my truck is diesel. With no codes, not even in memory, the mechanic has only my "mimics" of the sound, it doesn't give him a lot to go on to find and fix the problem, and until we find the source, I am afraid of towing my 5thWheel in this condition. Very sorry to Hanky for not saying (diesel first time) but I will pass all the Infos anyway. It might help to pinpoin