I just had service done at a cat dealer they changed out my oil and filters. They also greased the chassis. All the filters were changed except they did not have the fuel/water separator Filter in stock. So I left with the old one still on and traveled 130 miles from our home. I have one on order from a local NAPA auto parts store, should be here tomorrow. How hard would this be change out myself? Does the new filter have to be filled with diesel before threading on the fuel line? There is a local truck shop nearby, should I just let them do it for $70 in labor?