After my review of the LEGO Technic 42110 Land Rover Defender I received a lot of questions about the gearbox, how it works, does it really runs inverted, did I make any building mistakes etc. I decided to create another video to show the gearbox in details, demonstrate why I think it runs the other way around and give anyone a chance to take a closer look
at my build and find any possible errors.
Besides the video demonstration here’s a little written summary about the drivetrain of the Defender.
In a normal car the engine drives the wheels through the gearbox, in a LEGO car this is the other way around. By pushing the car the wheels are driving the fake engine through the gearbox.
If we take a look at the bottom of the car we can see that both axles have a differential and the wheels are driving a central differential. There’s a 8T/24T gearing on both axles, which means the speed of the wheels is significantly slowed down.
The power from the central differential is transmitted to the DNR selector through a series of gears.
If the DNR selector is in drive mode then the power is transferred to the right side of the vehicle to the hi/lo selector.
Here you can see that low mode the power coming from the wheels is again geared down. This is incorrect, as it will make the fake engine run slower. In a real car at a constant wheel speed a lower gear means a faster engine.
After the hi/lo selector the power is transmitted to the gearbox through an axle and it comes back on the other one.
And at the end it reaches the fake engine through a series of gears in the front.