At 2000 miles my truck developed a new aœflutteringa, aœticking sounda once all cylinders reactivated as apart of the dynamic fuel management system. After bringing the truck to dealership, they proceeded to replace the lifters, the exhaust system twice, and performed a computer reflash. The truck was at the dealership for over 45 days within the first 6 months of ownership. After all the repairs, the sound is still audible and getting worse. In addition to this sound, at around 30,000 miles the transmission has now developed an audible clunking sound that can be felt once on release the gas peddle under slower operating speeds. After trying to engage with GM on simply understanding what the problem is and why there is the need for so much repair on a brand new vehicle, I am candidly fed up and let down as long term GM customer.