X2, Sleepy. I always have the oil changed for my Duramax at Walmart. They use premium oil. I change my own fuel filters and buy them at an auto parts store not the dealer for half the price. I never go to a dealer, they mark everything way up. If I ever need work, I'll find a good independent diesel shop. So far no diesel work needed after 140,000 miles other than routine fluid and filter changes. -Mark.