Driving my new 2015 GMC $52,000 GMC Sierra, I noticed a distinct slipping/hesitation/general roughness when accelerating from a dead stop. The truck seemed to either have a transmission or engine problem. Took it back to dealership for them to check, and they indicated that this was "normal" and it was just the "cylinder deactivation" feature performing as designed. I explained to them that cylinder deactivation only typically happens at highway speeds and especially not from a stand still. They stuck by their story and again stated this was normal. My son came to see me and drove my new truck. Of course the truck hesitated and slipped from a dead start. "what's wrong with your new truck dad?" he asked. I told him it was 'normal and he just rolled his eyes. This is not normal for every Sierra that GMC makes with the 5.3 engine and 6 speed transmission would do this. I have read on numerous message boards and websites where this is an issue and GM needs to fix the problem. Also, the headlights are extremely dim and are barely usable. As others have stated, I can only see maybe 20-30 feet in front of me and not very bright at that.

- Eatonton, GA, USA

I had made a complaint to chapdelaine Buick- GMC that my brand new truck did not seem to go into four wheel drive. I was told to bring the truck to the dealership and they would check it for me. I was told by the service department that the truck worked just fine in four wheel drive. I then noticed that the truck seem to shift very rough and I called the service department and told them that something had to be wrong. The service department asked me to bring the truck back down to them the next day and they would take it for a test drive. While I was driving the truck to the dealership it shifted from drive into neutral.I coasted to a stop put the vehicle into park shut off and restarted the engine and then shifted back into drive and tried to drive again. This time the vehicle service engine light came on and the vehicle stayed in low gear and would not shift into a higher gear. The best speed I could make was 10 mph. I stopped the vehicle and restarted two more times. On the second try the vehicle did go into drive. I made it to the dealership and they took it for a test drive and upon their return gave me a loaner vehicle. They had to rebuild the transmission on my brand new truck which took about three days. Thankfully this event took place on a back road with little traffic. If it had happened on a busy road an accident might have occurred.

- Ashby , MA, USA