Eric Zbytowski

@gpraceworks Any update on your truck,? I just purchased a 2021 GMC Denali 2500 and it did the same thing you described 3 times now. Going to pass punch the throttle and as soon as I pull out it's like the transmission is missing gears and shakes the truck. In all cases I was running around 60~65mph, punched it, and pulled out as it was downshifting and starting to put the power down large shaking and shuddering. I was not pulling or loaded down. Basically just 2 of us in the vehicle. - The first time I pulled over and couldn't find anything wrong. I tried several times to repeat it that day and could not. (about 1500miles on the truck) - The second time again but I just back off the throttle, rolled back on, and continued my pass. (about 2500miles on the truck) - The third time (same day) I started recording my passes with my ODBII scanner and found that it looks like the transmission is slipping in comparison to good passes. It down shifts from 10th gear to 6th gear. Holds that gear but it was slipping on that event. In this case I backed off and pulled back behind the truck I wanted to pass. I tried to repeat it again several times but had no luck. Other than this issue it up shifts and down shifts pretty well in all other cases. Any others having this problem?