The fuel cap is located behind a hinged door on the driver's side of your vehicle.
For chassis-cab models, refuel the front tank first, or in instances when only a partial fuel fill is desired. An automatic transfer mechanism will maintain approximately equal fuel levels in both tanks, so no switching is required by the operator.
While refueling your vehicle hang the tether from the hook on the filler door.
To remove the fuel cap, turn it slowly to the left (counterclockwise).
Be careful not to spill diesel fuel. Clean fuel from painted surfaces as soon as possible. See "Cleaning the Outside of Your Vehicle" in your owner's manual. When you put the cap back on, turn it to the right (clockwise) until you hear a clicking sound.
Make sure you fully install the fuel cap.
If you need a new fuel cap, be sure to get the right type. Your dealer can get one for you. If you get the wrong type, it may not fit properly.