Just wondering what kinda motor oil you guys have been running. I ran the Rotella 15w-40 in mine from when I bought it with 27,000 miles till I had about 78,000 miles. Then I switched over to the Rotella 5w-40 synthetic. Shortly after this I had it at the dealer for an egr valve, egr cooler, and oil cooler kit. They had to drain the oil and replaced it with 10w-30 QSD, which I'm guessing is Quaker State Diesel, but correct me if I'm wrong. I'd think they would use Motorcraft oil, but I'm not a diesel mechanic. Anyways I just changed the oil last weekend and went back to the Rotella 5w-40 synthetic. Anybody here run that, reccomend it, not reccomend it. Anybody have any good or bad luck with any other oil? Figure this could help out about any 6.0 owner on here. Thanks for any feedback, guys.