The 2007-10 don't have IOLM (except, as mac says, in our heads), so it is better to read the owner's manual carefully and decide whether normal- or severe-duty fits your schedule. You won't go wrong with severe-duty in either case, but it may not be necessary. Use a good oil and filter regardless to help prevent deposits from building up on the innards. Think of it as taking care of your pearly whites