Ever wondered how does a differential work? Turns out, Chevrolet explained the whole thing perfectly, back in the 1930s.

Carmakers used to turn out tons of these videos, back when they had piles of money to burn, when people gave a crap about what was going on under their hoods, and when cars were new and exciting and mysterious.

These kinds of videos still churn out from manufacturers, explaining to us the secrets behind carbon fiber, hybrid drive, and whatever else is new in the automotive world.

What manufacturer-made instructional video is your favorite? Any era may apply, and we'll probably favor engineering information, but driving technique, roadway design, and anything else vehicular is fair game.