I can not for the life of me figure this out and searched to find nothing. Once I get a certain speed, it turns on, this noise. If I drop 1-3 mph it stops immediately. It is a fast buzz/rattle that gets loud the faster you go over 65. So loud that it's freakin annoying. It's hard to explain the sound, but it's like a rock on a tire that is going fast making that clicking noise just about 20x louder in my truck near the middle of the dash area. It just started to do this for no reason.