Have a 2020 2500 with a service body. It pulls to the left, i have to hold the steering wheel at 1-2 oclock to keep it going straight. It will take the truck up over the crown of the road and into oncoming traffic. The first alignment was done at 1500 miles and everything was in spec. Local dealership billed me for the alignment even though the truck still pulled. They tried to claim that the wear in the road was causing it. If i wanted them to keep looking into it i would have to pay for the parts replaced. They clearly dont know how to diagnose an issue. Took it to them to have the first service done, at my request, they moved the tires from side to side not front to rear. The truck would still pull to the left.
Took the truck to a different dealership at 5300 miles. A friend works at this shop but they dont have an alignment rack. He test drove it and saw exactly what i was talking about. Checked the rotor temps and they were all within 5 degrees of each other, indicating that the calipers are no dragging. Put the truck in the air, all the tires turned freely. He said to take it down to the chevy dealership down the street. It had its second alignment. Once again, everything was right where it is supposed to be. GM tech support is now involved. They are recommending the steering angle sensor be recalibrated.