8 Parts of an Automatic Transmission (and How They Work)
Most vehicles on the road today are equipped with an automatic transmission. For drivers, it is much more convenient to use an automatic transmission than a manual transmission.
With an automatic transmission, the driver does not have to change gears at different speeds. In addition, there is no need to use a clutch pedal to disengage the clutch. The vehicle performs all these actions automatically, so the driver only has to sit back and worry about steering, accelerating, and braking. There are good reasons why fewer and fewer car manufacturers offer vehicles with manual transmissions. While many car enthusiasts may not agree with this decision, the sales figures speak volumes.
An automatic transmission works like a hydraulic control system. This system consists of several moving components that allow the transmission to automatically change gear ratios while driving. In some cases, there are automatic transmissions that operate mechanically or electrically.
Parts of an Automatic Transmission
Below is a list of parts for an automatic transmission system. Each part has a specific purpose to keep the transmission running smoothly.
1) Friction Clutch
Friction clutches connect the gears to the drive shaft. This basically allows the motor and input shaft to rotate at the exact same speed, which in turn supports the friction that occurs between the transmission and the engine. This allows the vehicle to move.
2) Ribbons
Bands hold the gears in a stationary position. They are attached to the pistons, and when the pistons are actuated, the gears are blocked by the gear steel.
3) Spring Loaded Valve
The spring loaded valve is connected to the drive shaft speed sensor. The faster the shaft moves the valve opens further. This allows hydraulic fluid pressure to flow into the system. The slower the shaft moves the further the valve closes.
4) Load Sensor
Automatic transmissions use a load sensor to detect the weight and load of the vehicle. When you press the accelerator pedal, more pressure is applied to a cable attached to the pedal. Some vehicles use a vacuum modulator instead.
When the engine is under greater load, the load sensor can detect these conditions and communicate them to the engine control unit.
5) Change-over valve
This component controls the supply of gear oil to the bands and pistons. Each shift valve has a different working pressure. The higher the position of the shift valve, the higher the working gear pressure ratio.
6) Torque Converter
The torque converter is a miracle part that replaces the clutch mechanism in a manual transmission. In an automatic transmission, the torque converter is responsible for slowing and stopping the car while the engine continues to run.
7) Gaskets and Sealing Rings
Automatic transmission systems have various seals and sealing rings that prevent transmission fluid from leaking where it shouldn’t. 8) Shifter
Automatic transmissions also have a shifter, but it works slightly differently than a manual transmission’s shifter. With an automatic transmission, you don’t use the shifter unless you come to a complete stop (in most cases).
Sometimes you might use 1st or 2nd gear while driving, but only if driving conditions are unusually rough and the vehicle will allow it.
Many vehicles also offer some sort of “sport” mode that changes the transmission’s shift points and other variables to improve performance at the expense of improved fuel economy. Under normal driving conditions you should usually shift into Drive and then leave it there.