A torque converter automatic transmission uses fluid to smoothly transfer engine power to the gears without a manual clutch.
For many years, drivers on the Sunshine Coast drove vehicles with a manual transmission. Today, there are far more vehicles that use an automatic transmission.
Torque Converter
The transmission itself uses a torque converter to transmit power from the engine to the wheels. Therefore, a torque converter is a fluid coupling that sits between the engine and the automatic transmission.
Its role is to transport the engine’s power to the gearbox while allowing the engine to keep running when the vehicle is stopped.
This determines the speed and torque of the vehicle. But what exactly is an automatic transmission?
What is an Automatic Transmission?
An automatic transmission transmits the power of the engine through a series of gears that dictate the speed your vehicle drives. For example, if you drive at high speeds, the high gear will be used. While lower speeds mean lower gears.
What separates a manual from an automatic transmission is that in manual transmissions the driver shifts the gears. However, in an automatic transmission, the gear shifts are performed automatically.
Manual transmissions require the use of a clutch pedal. While automatic transmissions do all the work without any input from the driver.
The Parts of an Automatic Transmission and Torque Converter
The automatic transmission is a complex machine, consisting of several different parts that must work together in an efficient manner.
- Torque Converter – Connects engine to transmission
- Planetary Gear Sets – The gears that change depending on the speed of the vehicle
- Modulator and Governor – Sensors that detect when gears need to be shifted
- Clutches & Bands – Switches and engages the gears. They are controlled by servos
- TCU & Shift Points – The points in vehicle speed where the gears shift
- Output Shaft – Transmits the power from the transmission to the wheels
- Gasket & Seals – What keeps the transmission fluid inside and pressurised
- Transmission Fluid – The fluid that keeps the gears shifting efficiently
When you drive, the engine produces more or less power depending on how much you press the accelerator. The power goes through the torque converter with the help of the transmission fluid.
This converts the power to the transmission itself which then controls how much power goes to the wheels.
The planetary gear sets change according to the amount of power using the modulator and governor to set the proper gear. The clutches, bands, and servos switch to the appropriate gear based on pre-set shift points and the TCU. Once determined, the power flows to the output shaft which is then transferred to the wheels.
A Brief History of Automatic Transmissions
The automatic transmission was invented by Alfred Homer Munro in 1932. Munro’s original design used compressed air which didn’t work well but was the basis for the development of the automatic transmission.
General Motors developed the first successful automatic transmission in 1940 with the arrival of the Hydra-Matic Drive. A four-speed transmission for their Oldsmobile line, the vehicles were the first to not include a manual clutch pedal for the driver.
After World War II, other automobile manufacturers followed suit and developed their own line of automatic transmission. In the 1950s, the PowerFlite transmission was created by Chevrolet. Afterward, Ford came out with the Ford-O-Matic, both of which were two-speed transmissions.
By 1957, automatic transmissions dominated the US market and ever since, they have spread around the world. Featuring new improvements and designs along with different types.
Over the course of several decades, different types of automatic transmission systems have been developed. In our next newsletter will discuss these systems.
For drivers on the Sunshine Coast considering the purchase of a vehicle with an automatic transmission, knowing the facts will help you make the best-informed decision.
MillerMatics Mechanical’s team are experienced mechanics and have the qualifications and licences required to carry out this specialised work. Contact us or call on 07 5479 3638 and they can answer all your queries.
