According to our friends at Pickuptrucks.com, Mexican Border Officials have begun enforcing an seldom used law to take America trucks as they cross over the border.
With diesel fuel in Mexico at only $2.20/gallon, it is attractive for those who live in proximity to the Mexican border to cross just to fill up. This in itself is not illegal, but filling any auxiliary container not part of the factory fuel system is. The law is supposed to stop the transportation of combustible fuel over international bridges in vehicles not designed to carry large amounts of flammable substances.
If you are caught your truck can be impounded for several days to a week or more and a fine is assessd. Mexican customs officials have recently begun confiscating U.S. diesels in Ciudad Acuna, Coahuila, Mexico, across the border from Del Rio.
Also of interest, Mexico's diesel fuel is NOT low sulfer and can damage the emission equipment on 2007 and newer diesel trucks.
--Sean P. Holman
Tech Editor - Four Wheeler Magazine