Dert

I have a 2018 Sierra. Last night I was heading to the airport and I heard the whine. I had music on and thought “I don’t remember any feedback being in this song” as that’s exactly what the sound is like, guitar amp feedback. Happens at about 110km/h. This is the first time I ever heard it, I drive highway every week and I have no idea where it is coming from as this is the first time I heard it. This is also the first time I had 4x4 in auto as it was snowing. Taking it out of auto never changed anything, it’s almost as if it started it and now it’s a “thing”