Weird whistling . whining sound when revving car.
https://www.dropbox.com/s/tmavi6y0to...84928.mp4?dl=0
Worst case Sanario could be your transfer case.
What year is your car
How long have you had your car.
When did you start hearing the noise.
My car has a very faint whistle when I give it throttle in park or drive or neutral .
Checked for intake leak found nothing.
Did it in the old tranny and still has slight whistle with the new tranny from mercedes .
Installed by mercedes under warranty.
I only have 16000 plus miles on my car.
12 c300 4matic sport



