Everybody has their own opinion on this. I used a different break in technique and had it broken in by 100 miles,. I changed the oil at that point with 10-40 dino oil, and changed again at 900 miles with 20-50 synthetic oil. I will use synthetic from this point forward, in 20-50 because it never gets really cold where I live. Changed the rear with 80/90 hypoid gear oil at the 900 mile service.What type of oil????????????