Taking mine in on 23rd. Dealer told me 1 day and possibly a few hours into the next day. He said tech does diags on Mon/Tues. and tear down/rebuild Wed - Fri.
Same here. I had a 2017 2.7L and it was the biggest piece of junk I have ever owned. Had 4 oil pans and they finally replaced the block. It stranded me shortly after block replacement and I got rid of that sucker as fast as I could.
We went to Yellowstone last week and we rented Chevy 1500's with the 3.0L Duramax. What a great engine. We were getting around 40.0 mpg cruising. Fueled up and had over 800 mi range. Makes me want one in a GMC.