Shanghai Siken Industries Inc.

Web:  www.siken-inc.com

Email:info@siken-inc.com

 

Transmission function (in a car)

 

The transmission (gearbox) is the part of the drivetrain that transfers power from the engine to the wheels while adapting engine speed and torque to the vehicle’s needs.

 

Main functions

•  Converts and multiplies torque — Provides high torque at low speeds (for starting, climbing hills, or accelerating) and lower torque at higher speeds (for efficient cruising).

•  Keeps the engine in its optimal RPM range — Prevents the engine from over-revving or lugging, improving performance, fuel economy, and durability.

•  Allows the vehicle to stop while the engine is running — Via the clutch (manual) or torque converter (automatic), it can disconnect power flow.

•  Provides reverse gear — Changes the direction of power so the car can move backward.

•  Enables different driving modes — In automatic transmissions, it selects gears automatically based on speed, load, throttle position, etc.

 

Simple analogy

Think of it like the gears on a bicycle: low gears give you more force to start moving or climb, while high gears let you go faster with less effort once you’re already moving.

Without a transmission, the engine would either stall at low speeds or be limited to a very narrow usable speed range.