Out of the blue without any warning, no noises, my Chevy Traverse Park Gear simply stopped working, luckily my carwash person wasn't injured when he found out, he had parked my truck on an elevated parking spot and when he turned it off and stepped out, the truck slowing backed out, he noticed and quickly got back in a pressed the brakes, he had to move to a leveled parking spot and engage the foot brake to be safe, now since then I have been using the foot brake everywhere I park it! I took it to a couple of Mechanics, they tried to engage the park position manually and nothing, the only option is to bring down the transmission and the motor to open it and see what could be wrong inside, this is so annoying and expensive! I had this car for a little over a year and had so many issues! My next step is to contact GM and see if my truck has a special policy that might help me pay to fix it. Good luck to me!