Some other WF fella's talked about the only difference between a 20 gal and a 15 gal tank was a long plastic tube stuck down in the 20 gallon tank vent tube at the factory. If you wanted to pay for a 20 gal "upgrade" on the new Jeep you were buying, Chrysler would simply not put the tube in. Otherwise the tanks were identical. A couple guys attached some photos and step by step instructions on how to remove the tube, which I did. And now I have a 20 gal tank. I'm not sure how to attach the link to this reply.