Just did my first oil change 2 weeks ago, I think the truck has just a hair under 7k miles now. I'm sitting right about 18.4 average with about 50/50 driving. On the highway I'm usually cruising around 78 as much as possible. I have a new exhaust on there so driving around town is typically a bit more....spirited lol. This is on a 2018 Custom Crew Cab 5.3 2WD, not sure on gearing.
2018 Custom Crew Cab 5.3, Carven side exit exhaust, ebay intake w/ K&N filter, tint, 22" reps (just installed yesterday) and tonneau cover. Just gotta drop the rear a bit and add my stereo and I think I'll be done for awhile. Oh yeah... the truck just had it's first oil change last week lol