I have been running Valvoline High Mileage 10w-30 for the past year or two. After reading a few posts where people say their 4.0's run quieter with Rotella, I just bought a couple of gallons of Rotella T5 10w-30 at Wally World for $16.00 per gallon. Figured I would give it a try. Truck has 111,000 miles on it with no drips. Will see how it goes......... Also I use K&N oil filters.