New to TDR. Just purchased a '01 quad cab that was from an auto auction. It was a lease return, in excellent condt. with 60k miles. I have no history of what oil was used in the truck. Dealer must of changed it before sale as it's clean w/new filter. My question is what oil to use, I'm leaning toward Delo 400. Also what weight oil? That truck is all stock w/at and will tow 2000 lb. boat. Thanks in advance. Jeff