I have a new 2024 silverado 2500hd with the 6.6 l8t gas engine and allison ten speed. Have used mobil1 in the past along with penzoil platinum and I liked shell rotella gas truck while it was out. Previous truck was 2014 silverado1500 with a 5.3. So the new truck calls for 5w30. I changed the oil at 550 miles with mobil1. Dealer will do one free service at probably 7000-7500 miles. It has almost 2200 on it now. I drag around a bassboat sometimes, whole package is 3000 pounds. My camper loaded to camp is almost 5600 pounds. I use but don't abuse my trucks. Do not drive aggressively and I am about maintenance. Trying to decide what 5w30 oil to use. Usually do 6k oil,filter change and rotate tires. But might do this at 5k this truck. Ac delco oil filters to be used. Old truck was at 168k at trade in and was in running great. So, what say you? Oil brand and how often? I know lots of information but everyone on here seems thorough.