Have to take my 2020 at4 3.0 duramax to dealer today and drop it off. It is shifting very hard in the first 3-4 gears. Upshifting seems like it is slipping real bad and when you stop and it downshifts when it gets down to the lower ones it jerks really bad. Not sure what it is, they said they didn’t have a transmission tech there till Tuesday. Has anyone heard from f this before because they told me they have never had any issues with the 10 speed transmission’s.