Did you just put the moter in the truck? If I where you I would tripple check and make sure that it is actually leaking from there before you pull it. Oil leaks on these can be tricky. When I switched to synthetic I had a little oil running out around my icp sensor that ran along the groove between the head and the block, down the back of the head and down the driver side of the block by the oil cooler.
Just saying don't go yanking the motor out till you are absolutely sure.