Eli5: how can you roll start a manual vehicle but not an automatic vehicle?
In: Other
The tired of the vehicle are directly connected to the clutch disc by way of the transmission.
The flywheel and pressure plate (the things that the clutch are compressed between) are directly connected to the engine.
In a traditional automatic transmission the connection between the engine and transmission is a fluid coupler (torque converter) that works off of centripetal force, and you can’t make the force of the engine isn’t running. And in a traditional automatic transmission the transmission itself is hydraulic. But you the engine to run to produce that hydraulic pressure.
So when the engine isn’t running in a traditional automatic transmission there’s no direct connection between the engine and the tires. That’s why there’s a “park” in an automatic transmission. It’s a little lever that gets pushed into a space that stops the wheels from moving. If you just left an automatic car in gear when you turned off the engine. You would be able to push it.
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