19. The chassis travels down the assembly line inverted. As it moves along, components like the suspension, axles, driveshafts, rack-and-pinion steering, fuel tank, brakes, and hoses are all installed. The chassis is then turned right-side-up by machinery for the installation of the engine, transmission, transfer case, radiator, wheels, and tires. Interesting fact: The assembly line that mounts, balances, and adds the tire-pressure monitoring sensors to the wheels and tires produces a complete ready-to-roll unit every 12.5 seconds.