My 2019 Sierra 1500 does the same thing. Last night, for the 2nd time, left rear tire was on pavement while the right rear was in the snow. Tried to make a u-turn. Rear and locked up. Every turn made going home was a fight. All at 30mph or less. Backing into my parking spot was also a fight. Is something about to totally brake? Is it going to fail completely on a trip from NY to NC? What's the correct fix for this problem before it becomes a major issue? Bruce