so i just picked up a 06 f350, first diesel, and so far im loving it. i know about all the issues and i dont seem to have any of the symptoms, knock on wood. i want to do some general maintenance so i know its done and done right. ive searched and the concensus on oil seems to be 5w 40 valvoline premium blue. my question is, can i run 15w 40 premium blue instead. i cant find 5w 40 anywhere and i live in south louisiana where it gets to about 95-100 degrees during summer. also where can i order a batch of filters both fuel and oil (and if anybody has part numbers that would be great). besides fuel filter, oil and filter and cleaning of air filter should i look at doing anything else? thanks and i look forward to hanging out