LEGO automatic transmissions

[AviatorBJP] is building some impressive automatic transmissions using LEGO parts. Your best bet is to check out his YouTube channel as he’s got a slew of videos related to topic. We’ve embedded test footage of first and second generation vehicles as well as the most recent flywheel design after the break. But we’re getting ahead of ourselves, let’s look at how the system works.

Each transmission centers on a mechanism that includes hinged arms attached to a central axle. The arms are held together with a rubber band but as the axle spins faster, they overcome the elastic force of the band and begin to pivot outward. This pulls the shaft in one direction, moving its gear up to the next position in the transmission box. To test the system [AviatorBJP] uses a treadmill. A string is attached to the front of the vehicle to keep it in place and the treadmill is switched on to simulate engine power.

This design is quite brilliant, and he’s not keeping it to himself. If you’ve grown tired of the manual LEGO transmission you built, you can follow his multi-video build process to make one of these for yourself.

1st Generation

2nd Generation

Newest flywheel design

[Thanks Derp via Break]


  1. Mad says:

    this is just so ingenious !
    hats off guys !!!

  2. Alwar says:


    i want a lego!

  3. biozz says:

    finally! i was getting tired of the shifter in my lego car XD
    just kidding … this is some serious ingenuity and major props to the creator

  4. Erik Johnson says:

    @biozz This is your lego car?

    (actually, this reminded me of that article)

  5. crazy. reminds me of the old snowmobile flywheel clutch design

  6. biozz says:

    @Erik Johnson
    haha i wish

  7. Richardf says:

    One of my favorite things to do with Lego is build transmissions. Awesome find, can’t wait to try it!

  8. Mankysteve says:

    It’s working on similar principle to those old regulators on steam engines.

  9. Roberto says:

    The inventiveness is bow-worthy, but don’t electric vehicles already have high torques at low RPMs?

  10. pRoFlT says:

    @Roberto, Yah but this is an automatic transmission. With a transmission you can achieve greater speed! With the advantage of electric torque.

    This needs to be remote control, so we can see the speed on the street!

  11. pRoFlT says:

    p.s. whats up with the wheel in the back? Is that using momentum to keep the gears moving during gear changes?

  12. leafy says:

    @mankysteve, I think you’re thinking of a guvernor

    @roberto, I think that only applies to certain electric motors, certainly not brushed DC permanent magnet motors, they typically have awful low speed torque.

    @profit, I think that’s just to display the output from the transmission.

    I love this, its a great use for lego and a neat system, now he just needs to incorporate a synchromesh system ;)

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