Mattbmx63

I have a 2017 Sierra with the 6.2. Sometimes when I go to start it, it will crank for a second, start cranking very slow then back to normal. Other times it may barely crank for a second then start. Have load tested battery, no issue found. I just drove for 30 minutes, stopped to get gas, when I went to start the truck, very slow cranking for a couple seconds then normal cranking and it starts. Dealer claims no issue.... any idea's?

My 2017 8-speed had the flush at 22k, they just did a converter at 31k. Got it back, 100 miles later shuddering is back. It shifts worse now than ever and it seems to rarely go into V4 mode now. Not sure if they are doing something with programming as well. I have to go back and ask. I was told the new converter most likely is the same just from a different vendor. Anyone have any clue what is really going on with these things? They mentioned final fix beginning of 2019....