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Automobile transmission system refers to the assembly of gears and associated automotive components by means of which the power of the engine is multiplied and transmitted to the driving axle. It is also the system through which a driver shifts gears by the action of her hand on the gear lever or gearstick. A manual transmission system is known by several different terms such as standard transmission, stick shift, stick, or straight drive.

With the transmissions featuring a driver-operated clutch and a movable gear selector, most of them enable the driver to select any of the forward gears at any time. However in some cases such as the ones installed on motorcycles and some types of racing cars, the driver can only switch to the next-highest or next-lowest gear.


Automobile transmission can either be manual or automatic. The manual transmissions feature different gear ratios which can be switched to by engaging pairs of gears inside the transmission. On the other hand the automatic transmissions typically have gears controlled by brake bands or clutch packs for selecting a gear ratio. Another category of transmission is the semi-automatic transmission, which allows the driver to select the current gear manually.

Although, the current automobile transmissions comprise a set of four to six forward gears with a reverse gear, but automobiles with manual transmission consisting of eight forward gears have also been built. Manual, Automatic, Non-synchronous, Continuously variable, Semi-automatic, Infinitely variable, Hydrostatic, Electric variable, Electric and Hydrodynamic are some other types of automobile transmission systems.

Transmission System Components

The transmission system of an automobile is a complex piece of machinery and there are a number of different components that work in conjunction with each other to make it work. Some essential parts of the system are explained below.

Automotive Gears and Gear Parts

Automotive gears form the basic element of a transmission system transmitting rotational force to another device or gear. The difference between a gear and a pulley is that a gear is a round wheel with linkages, also called the "cogs" or "teeth," which mingle with other gear teeth to completely transfer the force. There are many different types of gears and based on their design and arrangement, they can transmit forces at different speeds, torques, different directions, from the source of  power.

Clutch

Clutch is an essential component of the transmission system that interrupts power transmission. It is installed between the engine and gearbox of an automobile. Clutches are made up of two rotating shafts. Of which one shaft is usually driven by a motor or pulley, while the other drives is meant to drive a
device. A clutch links the two shafts in such a way that they can either be engaged (rotate at the same speed) or be disengaged (spin at different speeds). Clutches are often classified as single plate friction clutch, mostly used in automobiles and trucks, or the multiple plate friction clutch, installed mostly in diesel engines and motorcycles. Further, they can also be classified as “wet” or “dry” depending on whether they are immersed in a lubricating fluid or not.

Gear Shifters

Gear shifters are a part of the gearbox which comprises shift forks and links the transmission controls at the drivers end to the synchronization. Thus enabling the driver to choose a gear ratio. Sometimes, to automatize gear shifters, different types of actuators such as a pneumatic, hydraulic, or electric actuators are used based on the space available around the drivetrain as well as the car type.

Output Shaft

Output shaft is a shaft that transfers motion from a primary mover to the part that's driven. In case of automobiles, the shaft transmits torque from the transmission.

Torque Converters

Torque converter is a type of coupling that is used to transmit rotating power from the automobile engine or the electric motor to a rotating driven load. In its simple application it can serve as a mechanical clutch engaging or disengaging the load from the power source. However, in its advanced application it can even be used to multiply torque if there's a lot of difference between input and output speed or rotation.

Transmission Axles

The term transmission axle refers to the central shaft for rotating the gears of an automobile. An integral component of the transmission system, it is sometimes positioned with a bearing or bushing inside the hole in the gears, thus enabling the gear to rotate around it.

Other essential components of the transmission system include parts such as Universal Joints, Differential, Torque Converters, etc.

Buying Tips

You can ensure quality automotive part supplies through the following buying tips.

1. Always prefer new auto parts instead of used ones.

2. Choose your suppliers carefully, establish a reasonable level of trust towards a supplier, through referrals, testimonial, or certifications.

3. Be wary of suppliers offering products at extraordinarily low prices.

4. Ensure the specifics of the products you require from the supplier, before placing the order, a sample inspection is often the best way to do it.

5. You need to understand the terms and conditions including warranties and guarantees associated with the supplies you order.

Industry Overview

Owing to the competition in the automotive industry increasingly attaining global levels, there is an immense pressure on the manufacturers to reduce costs. Further, a feature peculiar to the transmission industry is that transmission parts are investment intensive, hence it is more likely to feel the heat of global competition.
In addition, both economic and environmental concerns warrant that development of transmission system needs of be geared towards reduced fuel consumption as well as emissions, thus bringing them in line with the market dynamics.

At present about 80 percent of transmissions are developed by the car manufacturers themselves. However, experts opine that if auto part manufacturers begin to share licenses it could lead to a production of 93 million transmission by 2015, as compared to 69 million today.

Furthermore, increased mobility is also the need of the hour as car production too is estimated to increase by a big measure. For instance, at present there are about 800 million cars around the world, but by 2020 this figure would swell to a staggering 1.1 billion, witnessing a growth of 15 percent per year.

There are several upcoming markets in the automotive industry including Brazil, Russia India and China, which would also be the markets of tomorrow for the transmission industry.