How do automatic transmissions work?

This model is based off a Simpson planetary gear set. "A Simpson gearset delivers three forward gears and one reverse, plus neutral, and is commonly employed in three and four velocity automatic transmissions." You can read more about it here: en.wikipedia.org/wiki/Simpson_planetary_gearset

Almost all car on the road in the US are automatic. In Europe it is the other way around.

While watching, I felt like I understood everything. And then the video ended and I still have no idea how an automatic transmission works

Exactly every tutorial on YouTube showing how “automatic transmission works “ just showing how the planetary gears rotate. No explanation how why and what’s the “automatic “ thing there. No doubt, great job with 3D printing!

That's how the planetary gear set works. but the units themselves are essentially hydraulically driven. you now have to get into the operation of that system with the fluid pump, the valve body and torque converter. the latter being one of the most misunderstood components, not so much the gear box.

This is more like a planetary gear transmission rather than how an automatic transmission works.

How do I know author lives in USA? "Almost all car on the road are automatic" 🤣

This explains how the gearing works but not what makes it automatic. How/when are those shifts actually made?

I love when people are able to use tools, that people are really getting into, to explain science. Such as this makes it easier for the younger generation to understand this kind of mechanism without needing to go to college for engineering. Younger people already have their 3d printers so this becomes more relatable. Good video.

"Amost all cars on the road are automatic" Laughs in Germany

This didn't explain how an automatic transmission works? Just ow planetar gearing works, no? I mean, how does the gerabox determin which gears to use, isn't that the "automatic" part of it, which you didn't explain at all?

Toque converter is also very important part of automatic transmission, as it allows to make your car stay still without turning off your engine.

Nice. I'm still working on mine. Trying to figure out how to simulate the clutch packs. There's 5 of them and 3 planetary sets, as well as two 1-way clutches. I keep getting distracted with side projects. Will finish sometime this year I hope.

This explanation is as clear as mud!

The majority of cars world wide still use manual transmission. Up to 2018, the majority of cars sold in Germany had manual transmission, only in 2019 the automatic ones overtook them (55% automatic), however, this is for new cars sold, not cars on the road. Actually the reason why manual transmission will soon die out is not because of automatic transmission but because of electric cars. Also the majority of German automatic cars don't use an automatic transmission as shown in that video, actually they use the same transmission that a car with manual transmission does use, it's just operated automatically and has two clutches, which allows for very smooth transmission without any noticeable tractive force interruption while doing so.

Okay? So how does it automatically change the gears?

In the US “almost all cars on the road are automatic” there fixed for you

Nice job! Nevertheless what I'm missing here, is how this works automatically - you still manually select which handle to hold. This type of gearbox was selected for automatics because it is simpler to control. But how the car choose which gear to select? Was it always computer, or were there some clever mechanical ways (in older cars)?

Works every time without fail. Just search YouTube and you can fix your own car in no time! Thanks for the tutorial! Saved me thousands of dollars in repairs!

You have to manually switch the gears by holding the blue or red gear. The literal definition of manual. Maybe redo this one and show actual automatic shift based on the RPM.