Noise – Ultrasound range Who knows this?

Have a constant whistle on the highway several times after full load operation – independent of speed, sounds like an ultrasonic whistle and goes away only when I slow down and wait about 3 minutes. I have now shot that it comes from the turbo but don’t know it because you can’t locate it badly, but from the front it comes. Oh yes 3,0 WildTrak (at the time without a chip) as if it can’t be. I haven’t made a diagnosis yet but if I go to the dealer who can’t understand it because it takes 45min to the highway and that’s a rough trial ride. Does anyone know the problem??