Well I have been quiet about my truck mainly due to being in the buyback process and not wanting to jeopardize the process.
Now that it is complete I can give the Steps that were taken.
Truck had 6 sets of tires put on it
One new set of wheels
New axle shafts
New ring and pinion
New steering rack bushings
New front hubs
All of this did not correct the issue, matter of fact the hotter it got outside the more the truck would shake, leading me to think it was transmission related.
I will say your first line of defense and advocacy is the service manager or in GM terms the Customer Experience Manager (CEM). He/She will speak on your behalf to the DMA who is the district rep.
In my case my CEM was great to deal with and I treated him with the utmost respect. If you encounter a CEM that is not helpful go somewhere else. Do not be demanding and let them run their process.
In my case I was in a rental for 52 days.
Hopefully this helps with you all who are experiencing this issue.
Just remember you can get more bees with honey.