I am having the exact problem in my 2020 1500 RST RWD crew cab. Just got the call from the dealer when I took it in. they said they do not know what I was talking about and could not replicate it during the test drive. mind you they only drove 6 miles at 40mph. they said it is because the bed is empty and that it is lighter. I agree that the bed is lighter, but of all of the other chevy's I have owned...I have never had the rear end swing, unless it was on a wet road or in sand and i did it on purpose. is upgrading the shocks really the best way to fix this, other than putting 200-300lbs of weigh in the bed? seems like this is a design flaw and a potential liability. I have though I was gonna roll over a couple of times when it happened to me.
