I am looking for some help or guidance. I have a 2020 Z71 Silverado 1500; Duramax 2.7L turbo diesel that has 18.5K miles. At about 5K miles, I ran into the 1st set of issues and had at two separate dealerships to attempt repairs. The repair code was for the transmission and TCM wherein the transmission would skip gears, run rough and you would feel as best as I can describe a a major flutter/delay when accelerating. The external wiring harness was replaced - did not fix the issue, computer replaced - didn't fix issue, after having for 3-4 weeks they finally did a complete rewire of the internal wiring harness to the transmission. For a time it appeared to fix the issue.

Now, for the last 1K miles a sensor never tripped but I encountered the same type issues and it seemed to run rough especially in higher gears. Two weeks ago, the sensor tripped and put me in safe mode. I created to a dealership wherein they replaced the TCM. Right after I still experienced similar issues and higher gears occasionally slipped. Two days ago the sensor tripped, putting me in safe mode again. Upon calling GM, I am still waiting on the customer service contact to call me and the dealership has stated two weeks to even look at.

Questions:
1.) Has anyone else faced this type of continued mechanical issue with a newer Z71 Silverado?
2.) I am stuck calling the same general line that connect to India, (800)-222-1020. Is there any other to get a US agent?
3.) Has anyone been able to successfully get resolution with a state lemon law? If so, how/what happened?