Thomas construction

I have a2016 GMC Denali with a 5.3 litre 8 speed with 60,000 kms when I leave in the morning shifting at slow speeds is erratic sometimes , on occasion smooth the truck shakes as if the tires are out of balance, I had them rebalanced to no avail , took to dealer , he changed the transmission oil and did some reprogramming as per GMC bulletin that took out the high speed 110 kph shudder now that shudder is at speeds up to 80 kph The dealer tells me warranty is now up but they will try again , so back for a third time to see if reprogramming can correct my shifting problems started at 10,000 kms dealer keep saying it’s a truck , that’s normal i ve had GM’s all my life over 15 trucks , this is my worst one ever and I think it’s my last ! My tundra is fantastic!!!