CREW CAB. A component which prevents a leak at the Fuel Level Sending Unit. A round Ring used to seal between the diesel exhaust fluid Pump and it's mounting surface. Aft Axle Fuel Tank. Device that seals the Tank around the Fuel Pump. Dual Fuel Tanks. From 03/01/04. Fuel Pump O-Ring. Fuel Tank Sending Unit Gasket. Midship Fuel Tank. Part cannot be reused/reinstalled. Single Fuel Tank. sender seal. Tank Sending Seal. Diesel Emissions Fluid (DEF) O -. Diesel Exhaust Fluid (DEF) O -. Lock. Module o -. Retainer. Included with: Fuel Pump, Fuel Pump assembly, Level sensor, Part is included with Fuel Pump, Sensor kit.