I was in this same situation once. Brought work truck to dealer for service cause our company wanted paper trails for all records. Picked truck up and drove three hours to our next job in the middle of nowhere. I could smell fuel but just figured they spilled a little and it's burning off. No so much!! They had cross threaded the cap and cranked it down as far as they could. Well, it wasn't far enough and fuel was leaking. I did not have the proper tools at the time. So, the channel locks I had only made things worse. I welded two bolts to a 12" flat bar at one end a couple of inches apart. It looked like a capital F, if you can picture that. I then drilled two holes the same distance apart in the filter cap. Stuck the bolts in the holes and screwed the cap right off. A new cap is required after, but the cap was already damaged anyway.