Information on Diesel Exhaust Fluid (DEF), how to properly fill your DEF tank and when the proper time is to fill it according to the message center in the instrument cluster.<br /><br /><br /><img src="http://ll.broadbandsports.com/images/39434_thumb.jpg" alt="2011 Ford Super Duty Diesel Exhaust Fluid (DEF) Tutorial" title="2011 Ford Super Duty Diesel Exhaust Fluid (DEF) Tutorial" width="150" height="90" alt="2011 Ford Super Duty Diesel Exhaust Fluid (DEF) Tutorial"/>
