12 quarts for the 2004 common rail diesel. i use delo 400 in mine (2004 dodge 2500 diesel quad cab short bed, converted to run on straight veggie oil) and highly suggest you do the same. it will greatly increase the quality and quantity of the life of your truck.
depends on the year, auto or manual, High output or not. on your dodge cummins, the front cover on your engine will have a tag with the HP and ft lbs of torque on it. It will be on the drivers side on the edge of the cover. You might want to take a rag with you to wipe it off.