Problem with that is the problem went undiagnosed for the same problem the first 5 times. It only applies if they diagnose the issue and can’t resolve it.
I bought a 2017 Silverado 1500 double cab and have had all the same back end issues. Been to the dealer 7 times to “fix” the problem. Never once have they looked into greasing the springs or anything. To be quite honest, it scares me to haul my horse with this thing. The noise sounds like the back end is going to drop off it is so loud now. Sincerely disappointed in buying this vehicle and if they don’t fix soon, I will never buy a Chevy again.