While on a road trip down south, last January, had a GM dealer only put 6 quarts in my 14 Silverado. When looking at the service slip, I noticed that they listed my truck as a 13 Silverado, and questioned them about it, as the 13's only took 6 qts. They said just a computer glitch, and that the right oil, and right amt was in the truck. I should of checked the dipstick before I left. I did watch my oil pressure gauge as I drove back to my wife's sisters house. Sure enough, two miles down the road, the oil level warning went off, pressure was still good, and I pulled over and shut the engine off. Called dealer to bring some oil, and they said to drive it back to dealer, as they were too busy to send someone. I said I wouldn't do that, and she said there was nothing they could do then, and hung up. I called GM, and they had someone there in 15 mins. Hopefully that service advisor was fired. When I got back home, 1400 miles, I called GM again, as when the kid showed up to top my truck off, it was with a 5-30 Pennzoil jug, but said not to worry, as it was the right oil in the jug. I told GM I had no confidence in what oil was in the truck, and I wanted it changed out. They asked if I had confidence in my home dealer, and I said yes, and They authorized another free oil change.