I have a 2012 Chevy Silverado 1500 LTZ with the 5.3 Vortech flex and installed a tuner by bully dog GT gas. After doing some research I found I wasn’t the only one with this issue but when downshifting it almost locks the rear end as if the torque converter‘* getting stuck or something and it’* almost consistent every time I know I push on the pedal and let the truck Township on it’* on but doesn’t if I’m in manual mode. It’* exaggerated when I in my settings in my tuner choose a more aggressive shift pattern and this problem only seems to be progressing. When discussing this with a bully dog they say it’* an issue they’ve never heard of and don’t have a specific remedy other than updating my tuner it also after installing the tune every time will turn the check engine light on for communication issues to the ECM etc. which they tell me is normal and to disconnect the battery and reconnected to reset the light. I am a mechanic Who also has a license has a small technician and don’t claim to be anything special or know everything but I do know that you should not have to do what they’re telling me to do in any scenario as a procedure for tune or anything else at that . The tuner wasn’t cheap ***** would’ve passed it by now but I do need it because I do have a 28 foot travel trailer and use it very frequently so I’m not in a position to purchase a new one at the moment does anybody have any suggestions information or direction?