2000 Dodge Truck trouble

You'll have to replace the timing cover gasket. This requires removing the fan, fan shroud, belts, pulleys, etc. The timing cover is located on the front of your engine block behind all of the pulleys, belts, and fan. I would recommend taking it to a garage to have fixed unless you want to do it yourself. It will be a lot of work though. I have inserted a picture and circled the timing cover to show you where the timing belt is and what it looks like. Now, yours may look different than the one in the picture since it's a different engine, but it gives you a general idea of what one looks like.