Thank you for posting this info. I just got my brand new Sierra back from the dealership after having the triple flush done because of a bad vibration. Still within the 200 mile window and now it doesn’t shift right seems to get hung in between gears downshifting. So I’ll run the 200 miles as instructed and head back to the dealership for more “fixes” 55k truck only 2700 miles on it and appears to becoming a paper weight soon. Contacted the lawyer so hopefully I’ll hear back soon.
But thanks again for the info.