How Differential Gear works

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An evening pause: Though the first 1:50 of this very well done 1930s industrial is somewhat irrelevant and can be skipped, I think it is worth watching anyway. And the rest does a great job of explaining this mysterious piece of automobile equipment.

Hat tip Edward Thelen.



  • mpthompson

    I saw this several years ago in the Internet Archive as part of the Prelinger Collection which is a massive collection of 10,000’s of “ephemeral” (advertising, educational, industrial, and amateur) films spanning much of the 20th century. There are many other similar movies if you care to look for them at:

  • wayne

    Edward– good selection.

    The Jam Handy Organization produced 100’s of these short “industrial” films on topics such as this, and Chevrolet was a big client for over 30 years.

    The folks have an extensive collection, all of which are available on-line, in numerous downloadable & streaming formats, and all are in the public domain & free for use.
    Tangentially– when you visit–check out the Archive’s (growing) collection of public domain Feature Films. Lots-o-obscure material, you can’t find anywhere. (Over 4,200 Titles.)

  • wayne

    you beat me to it!

    Highly recommend the Archive!
    You can get totally lost in their various Collections and download hundreds of gigabytes of audio/video.
    (-They also have an extensive collection of digitized 78 rpm records as well.)
    Their collection rivals the Library of Congress in scope, with the complete upside that you can download everything they have, immediately, for free, in numerous formats.

    The Archive is also part of “Project Gutenberg”– they designed inexpensive, specialized scanning-equipment, using off-the-shelf components, and have been busily scanning & digitizing literally millions of books and other “ephemeral” texts.

  • Joe

    Great vid Edward, many people, including some fellow mechanics don’t equate levers to gears or gears as levers and torque multipliers, lots of fun!, this is torque being applied to to different sized levers equally.

  • Alex

    To all: Automatic Transmission, How it works ?

  • wayne

    Good video!

    Another Jam Handy Gem, that directly address’s Joe’s comment:

    “Spinning Levers”
    Jam Handy & Chevrolet 1936

  • Steve Earle

    Great video! I now have a much better understanding of how that part works. The MC riding team was a bonus :-)

  • Mitch S.

    Love those old training films.
    They put real effort and production value into them – really tried to engage the students.

    Here’s a favorite.
    It stars Rube Goldberg of the famous contraption cartoons.

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