Hello all, Newbie here. I just purchased a 2007 Chevy 2500HD Duramax crew cab short box and am in need of some advice as I have never owned or driven a diesel truck. I bought it from a dealer and as usual they know almost nothing about it's history. They gave me the Carfax report but all that told me was that it was in a couple of accidents and I'm the fourth owner. They also gave me a vehicle history report that shows the EGR valve was replaced at 58,000, a rear axle seal was replaced at 51,000 and an endgate latch was replaced at 13,000. I'm guessing that was just warranty work history so other than that I'm flying blind and since I'm OCD about maintaining my vehicles I need to know what to do now. The pickup has 169,900 miles and according to my VIN decoder is an LBZ with a 6 speed Allison and LT1 trim. It's all stock and seems to be in pretty good shape outside of some rust starting under the fender wells and a few hail dings. I'm going to try to find the most recent owner to see if he can give me any more background but if not I'm going to go from here. I'm thinking with 170,000 on it there must have been some engine or drive train work somewhere along the line. All the dealer did was change the oil, put in 2 new batteries and replace 2 glow plugs. If I can't get any reliable history I'm going to take it to my mechanic and have all the fluids and filters changed first. What I'd like to know is what you guys recommend for fluids and filters and what else I should have done or checked at that time. The dealer put Delvac 15-40 in the engine. How often do you recommend I change the fluids? I will probably put about 3,000 miles a year on the truck mostly pulling a 10,000# 5th wheel camper so it will sit around a lot unless I need a 4x4 in the winter. I'm thinking it has more than enough power now so I don't plan on any mods or tunes unless you think they are worth it. I've been doing some research online and seen some buzz about FASS and Air Dog fuel filters. Are they worth the expense? I would appreciate any advice or comments you guys have, Thanks. Oh by the way, I paid $15,500 for it. Was that reasonable?