Backyard tech

Hi Newbie here. My mother in law recently purchased a low mileage 2019 silverado. I noticed a clunk as she pulled in my stone driveway. Apon checking with the right rear wheel on and pushing in and pulling it back. I felt alot of end play and heard the clunk in the axle.So much that I even saw the rotor move with the wheel. Also checked the left side low an behold same amount of excess end play. Headed to the dealer this week. I see alot of posts on this issue here. I am not a gm tech or owner. But it appears from my inspection this is an issue in the rear differential axle end play. Hope this may help others with the same issue