One problem related to transmission slip out of gear has been reported for the 2017 GMC Sierra 1500. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2017 GMC Sierra 1500 based on all problems reported for the 2017 Sierra 1500.
After coming to a complete stop at traffic stop light truck's transmission made a loud "clunk" sound. When attempting to accelerate on the green light truck, initially would not move then it lerched forward but would not shift out of first gear. Pulled off main road and into a parking lot where I shifted truck into park and turned off the engine. After waiting a couple of minutes I restarted the truck, shifted into drive and pulled back onto the street, but the truck still would not shift out of first gear.