Not necessarily mine, but a relative had a 2014 Mercedes ML350 Bluetec and it was in and out of the shop persistently for the same issue for almost a year and it was brand new at the time. The issue was when making a low speed turn (left or right--like out of a plaza) and while accelerating the transmission was literally stuck in 1st gear, not letting you go quicker. I didn't believe the relative until I got in it and it happened to me. The techs at the Mercedes dealer were the most senior Mercedes technicians in all North America, weren't able to figure it out. They sent the codes on the computer back to Stuttgart and the most senior Mercedes techs in Germany weren't even able to figure it out. So my relative ended up using the lemon law for Mercedes to buy the vehicle back and Mercedes was more than fair in their buyback offer.