Like many other Mustang models, the car's gas tank is held in by metal straps. Bolts attach the straps at one end; pins on the other end allow the straps to dangle when the bolted sides are loosened. Chris chooses to remove the pins as well to drop the tank out of the car. The tank in '05-current Mustangs crosses over the driveshaft, so in order to drop it out of the car, the driveshaft must be removed. There's a crossover tube in the tank to get fuel from the non-pump side of the tank.