My fist oil check, truck is a 2017 5.7 with 63,000 miles, I bought truck with 30,000, don't know oil change history prior to that, I try to change oil in the 4-5 thousand mile range, The first 15,000 miles I used Royal Purple 5w30 with RP 20-820 the next 30,000 has been 1 5w30RL and the next 2...