A Gearbox Specialist’s Guide to How a Gearbox Works

However, even if you have been driving for years, chances are you haven’t paid much attention to how your vehicle - and the processes it relies on - actually work. How many times have you changed from first to second gear without really thinking about the mechanisms behind it?

Unless you are a car mechanic or a gearbox specialist, you probably haven’t had to think of this before. However, whether you rely on your car for your daily commute or you only ever drive on weekends, it pays to have at least a basic understanding of what’s going on in your gearbox. This can help you become a safer driver and gives you a better chance of identifying potential issues.

At Gearbox Specialists, it’s safe to say we know a thing or two about gearboxes and how they function. Below, we’ve put together a basic guide to how manual and automatic gearboxes work and why they’re so important.

Firstly, let’s take a look at what a gearbox actually is. In the simplest of terms, a gearbox is a mechanical component containing gears. These are rotating units designed to interact in a way that affects the speed, direction and torque of a machine, such as a car or industrial machine. When engaged, the gearbox transfers energy from one gear to another in order to achieve the desired effect. 

In mechanics, gearboxes are part of a bigger system called the transmission. The transmission is responsible for transferring power to the machine; i.e. the transmission is responsible for making a machine ‘go’. 

When this relates to a vehicle, the transmission includes:

● The gearbox

● The clutch

● The prop shaft

● The differential

● The final drive shafts.

These components work together to affect the speed and torque of a vehicle, two things which greatly affect the quality of driving. By transferring the rotational power created by the engine to the wheels, you can control the car when accelerating, deaccelerating, driving around corners, driving up and down different gradients and during any other road conditions.  

If the transmission system fails to transfer energy between mechanical components correctly, it will put undue pressure on the internal combustion engine and you will notice shuddering and shaking as you switch gears.

Now that you have a basic understanding of what gearboxes are and what they do, it’s time to delve into how they function. 

When it comes to cars and other types of vehicle, there are two main types of gearbox: manual and automatic. With manual vehicles, it is the responsibility of the driver to identify when it is time to change the speed and torque of the vehicle. With automatic vehicles, however, the internal transmission will adjust the gears automatically.

Here we discuss the processes in more detail:

In vehicles with manual transmission, the gearbox is typically positioned between the engine and the clutch. The process of switching gears varies slightly depending on the type of gearbox in question, but typically it is operated as follows:

● When the driver pushes down on the clutch pedal, the engine and transmission separate to allow the driver to operate the gear stick. 

● After the driver has done so, the selector rod for whichever gear they have selected puts the correct mechanisms into motion. For instance, if the driver moves the gear stick into the second gear position, the collar situated between first and second gear is forced to mesh into second gear. When the gear bearings aren’t in the locked position, they continue rotating

● When the accelerator is engaged and the clutch is released, the vehicle will start to move. 

There are seven gear positions available, including the first, second, third, fourth, fifth and sixth gear, in addition to reverse. Each gear is operated by its own wheel, which is a metal plate with ‘teeth’ which mesh together when engaged. 

First gear offers the lowest speed and the highest torque, whereas the sixth gear allows vehicles to travel at the highest speed but offers the lowest torque. When in reverse, cars can drive backwards. When a vehicle is not in gear, it is in ‘neutral’. During this position, rotational power cannot be transferred from the transmission to the vehicle’s engine and it cannot ‘go’. 

Typically, larger gears provide more torque (otherwise known as ‘turning power’) and lower speeds, whereas smaller gears offer higher speeds and less torque. This is why you move through the gears, from first gear upwards, as your vehicle’s speed increases. 

Unlike manual vehicles, automatic models aren’t operated with a driver-controlled gear stick. For this reason, vehicles with automatic transmission don’t have a clutch. Instead, the driver either pushes the acceleration or the brake pedal to control the car. The speed and torque of the vehicle are controlled automatically to imitate manual transmission cars - but how?

During automatic transmission, every component connecting the vehicle’s engine and wheels is also linked to a torque converter. In effect, this is a substitution for the clutch pedal. Torque converters are mechanisms which direct the rotational power of a machine to its input shaft bearing via transmission fluid. 

Automatic vehicles use sensors to figure out when it needs to change gears. When it’s time to switch gears, the torque converter disengages the engine and the transmission. To achieve the same effect as manual transmission systems, the vehicle’s torque converter moves the transmission fluid between the car’s impeller and turbine to create varying forms of pressure. 

Unlike manual transmissions, automatic transmission systems don’t have a separate wheel for each gear. Instead, the vehicle uses a gear system which relies on three components: sun, planetary and ring gears. 

When the torque converter identifies that the car needs to change gears, it engages the sun, planetary and ring gears with the pressure created by the transmission fluid. The gears then mesh together in different combinations to achieve the desired effect. 

It’s no secret that gearboxes are complicated systems, which is why it is always recommended that you leave repairs and rebuilds to the experts. Whether you own a vehicle with a manual or automatic gearbox, it’s essential to trust the professionals with any maintenance or repair solutions to ensure you receive the best possible service.

After all, when it comes to dealing with the internal mechanisms of your vehicle, you need to be confident they are functioning efficiently, safely and legally. Any problems could cause your vehicle to drive inefficiently, putting undue pressure upon your bank account and the planet. They could also affect how much control you have as a driver. A lack of gear control could seriously impact how safely you can drive, and may have devastating consequences.

To make sure your automatic or manual gearbox is being inspected by only the best in the industry, call us at Gearbox Specialists today. 

If you are looking for repair and replacement services for your automatic gearbox, manual gearbox or vehicle clutch, then you needn’t look further than Gearbox Specialists. Based in Bournemouth, we are proud to extend our invaluable knowledge, resources and experience to help customers in the local area with top-quality clutch and gearbox services. 

We’ve been in business since 1978 and since then our team has gone from strength to strength, making us the go-to clutch and gearbox repair and replacement professionals in the Bournemouth area. 

For more information about our range of services or to see how we could help you, please don’t hesitate to get in touch with us at Gearbox Specialists today. Our team of manual gearbox specialists and automatic gearbox specialists are always happy to help.