I also recommend a 15W-40 oil like Mobil1 Delvac 1300s, Pennzoil Long Life 15W-40, Chevron Delo 15W-40 or Shell Rotella T 15W-40. It seems the 4.0 likes a heavier weight oil than the 10W-30 DC specs for it. The best UOA's on the 4.0 here have been with a 40W oil. FL-1A, ST8A, or L30001 are acceptable filters for the 4.0.