I parked my 2018 traverse in my driveway (slight slope) and two hours later it ROLLED down the driveway. It did not slide, the front and back tires turned. This happened once last year but I thought I was crazy and left it half way down the driveway. This time I have it on camera as it rolled.

I took it to the dealership today, they found nothing wrong with it. They called someone at the engineering department at GM and were told they have never heard of this and it must not have been in park. The dealer told them it was 100% in park and if it wasn't then I would not be able to turn the car off (this happend 3 years ago and they had to replace something in the shifter). They have no idea what is wrong and their solution was to make sure my parking brake is on. Funny enough my parking brake broke on the way to the dealership.

Has anyone heard of any issues like this? Or have a suggestion on what it could be?

 

I had a similar issue. Did you end up getting anywhere with GM on this?