I do beleive Valvolene makes the oil for Mopar. I have changed out many of these CTD trucks to synthetics, and have found anywhere between 8,000 and 12,000 miles is a good time to change over from petrolium to synthetics. Just get a Group IV based fluid to get the best in synthetics.MFenza said:does any body know who is making the oil for mopar ? is it Rotella or Mobil Delvac? and at what mileage do you reccomend changing to synthetic I have 10,000 miles on the truck and I am wondering if that is to soon Matt 2004. 5 3500 4X4 Silver Dually Laramie![]()