Those of you considering a new pick up in 2011 should be aware of the new EPA guidelines. Ford, GM and Chrysler now include a five gallon [ approx ] tank of Diesel Exhaust Fluid on their diesel trucks. The DEF, called Urea is sprayed into the exhaust to lower emissions. Most trucks will travel 5000 miles on a tank. Mileage of reduced numbers to 2500 to 3000 miles when pulling trailers are now being reported. When the Urea level gets low owners are advised on the dash the speed limit is reduced to 55 mph. Next mesage will be 50 mph for 300 more miles. If the reservoir does not receive additional fluid the motors are reduced to idle speed only. The Diesel Exhaust Fluid got the name Urea due to a chemical make up similar to urine.