Jumping on this thread. Just bought a 2021 RST Z-71. It had 220 miles on it. Someone bought it and turned around and traded it in so i got a better warranty being it was a GM Certificate used truck. It was between this truck and and new Silverado LT Z-71. I went with this one because of the addrd warranty and it only had 220 mes on it. Didnt notice the noise in the rear end until on the way home and started paying closer attention! Callig Monday to ask about it.