I took my 2021 Ram 1500 5.7l Big Horn in to the dealer for an oil change back in March 2022 for the 1 year oil change at 3,583 miles. I got to looking at the receipt,
no charge, but they put in a 5W20 synthetic blend. Man I was pissed, i had assumed they'd put in full synthetic. I asked the service advisor and he said only the 6.4L
and the diesels call for full synthetic. He also said I needed get the oil changed every 5,000 miles or one year. So I came home and after a couple days I noticed an oil drip. I crawled under and snugged the oil plug up a bit. That worked.
I was still mad and I'm a believer in using full synthetic, which I've used for years in my 2001 Chevy 2500HD, 8.1L gas truck, and other vehicles. So I got online, found the exact Mopar oil filter they used and did another oil change myself using Pennzoil Platinum 5W20 Full Synthetic with filter change. In March 2023 when I go in for service I'll definitely request and pay for full synthetic or bring in some Pennzoil Platinum myself.
BTW, bought some extra stock rims and installed 4 new Cooper AT3 XLT Load Range E tires and kept my original rims and Bridgestones. I running 50 psi in them and they run great on the highway and they are very quiet. I went with the heavier tires because I pull a 7500# TT and didn't like the squirm in the original tires. I'll try 65 psi when I'm towing. I have already installed Air Lift 1000 in the springs and a solid Helwig sway bar. I've also upgraded to a Fastway e2 WD hitch rated at 1,200# tongue/12,000# trailer weight.