2019 3500 Denali crew cab dually, vibration in rear of truck over 60 mph, vibration from the day I picked it up and got on PA turnpike, tires were balanced 2-3 times to no avail. Dealer put PICO unit on and drove but found nothing. Has anyone had the same issue, it feels like a driveshaft balance issue, I had the same thing on 2007 Silverado crew cab with single rear wheel, driveshaft was balanced and perfect after that.
I have 26K miles and need fixed before we get to the 36K end of warranty.