What Is A Car gearbox/Transmission? Learn About Cost, Location, Replacing etc.

The gearbox (also called a transmission) is a big and vital component of any car with a combustion engine.

Let me explain what the gearbox is, where it is, what it does, cost of replacement, and much more.

I’ll explain it all in plain English, so anyone can follow.

What Is the Gearbox on A Car?

The gearbox, also known as a transmission, is a significant component in every car. Its primary function is to transmit the power from your engine to the driving wheels using gears. This allows you to control the power delivered to the wheels.

In most cars, there are two main types of gearboxes: manual and automatic. Manual gearboxes are the ones where you have to shift gears manually, using a clutch pedal and gear shifter (often called a stick). These gearboxes give you total control over the gear changes, thus making your driving experience more engaging.

Internals of a manual transmission contain several gears that you can select depending on your speed and driving conditions.

On the other hand, automatic gearboxes do all the gear shifting for you. You don’t need to operate a clutch pedal, allowing for more comfortable driving, mainly in stop-and-go traffic.

A typical car transmission consists of three to six gear sets, as well as a series of gear trains. These gear trains are essentially belts or chains that run along the outside of two or more gears, allowing the driver to control the power delivery to the car. The gearbox is crucial for efficiently transmitting your engine’s power to the wheels while ensuring smooth and responsive driving.

What Does A Gearbox Look Like?

Think of a gearbox as a housing that contains gears and the gear selector.

Automatic transmissionThe gears come in different sizes and shapes, resembling cylindrical cogs meshed together. Inside the gearbox, you may find a combination of helical gears, with teeth cut at an angle, or even spur gears that have teeth parallel to the gear’s rotation axis.

The gear selector mechanism, whether it’s a gear stick or an automatic selector, allows you to pick the right gear for the desired driving situation.

The gearbox itself can be quite compact. Imagine a metal box housing all these components, typically bolted to the car’s engine.

Manual transmissions will have a gear stick to shift gears, with the help of a clutch pedal. Meanwhile, automatic gearboxes manage gear changes electronically, without a clutch pedal.

What Are the Main Types of Automatic Gearboxes?

One of the most common types of automatic transmissions is the hydraulic automatic. This type uses a planetary gearset, hydraulic controls, and a torque converter to smoothly shift gears.

You might also come across the continuously variable transmission (CVT).

This type of gearbox doesn’t have fixed gears, but instead uses a system of pulleys and a belt to provide a seamless range of gear ratios. As a result, your car can achieve optimal efficiency and performance, especially in city driving conditions. The CVT does have its drawbacks, though, with some drivers finding it less responsive and not providing the same engaging driving experience as other types of automatic gearboxes.

Another type of automatic gearbox you’ll find is the automated manual transmission (AMT), which is sometimes referred to as a robotized manual. This type of transmission is actually a blend between an automatic and a manual gearbox, using clutches and actuators to automatically change gears for you.

While AMT gearboxes can offer fuel efficiency benefits and a more engaging driving experience relative to hydraulic automatics, they can be less smooth in their gear changes.

Finally, there’s the dual-clutch transmission (DCT), also known as a twin-clutch or direct-shift gearbox. This type of automatic transmission uses two separate clutches for odd and even gears, allowing for quicker and smoother shifts than a traditional automatic or AMT. DCTs are popular in performance and luxury cars, where drivers value responsive and sporty driving characteristics.

Where Are Gearboxes Located in Cars?

The gearbox (or transmission) is typically located near the car’s engine. Its position varies depending on your car’s make and model, but you can often find it under the hood or beneath the car between the engine and the drive wheels.

CVT transmission position under car

Finding the gearbox in your car isn’t too difficult. You can usually start by consulting your vehicle’s user manual, which often contains diagrams or instructions on locating it. If you don’t have a manual or can’t find the information there, an online search for your specific car model should help you locate it.

In some cases, though, getting to the gearbox might be a bit challenging, particularly if it’s located underneath your car. You might need to raise your vehicle using a car jack or lift and support it securely on jack stands. Additionally, depending on your car’s design, you may need to remove other components or covers to access the gearbox more easily.

How Long Does A Gearbox Last?

In general, an automatic transmission can last up to 100,000 miles, while a manual transmission can last over 120,000 miles if properly maintained and operated.

Regular maintenance ensures the longevity of your gearbox. This includes checking for leaks, changing the transmission fluid, and addressing any strange noises or issues promptly.

How Much Do Gearboxes Cost?

A brand-new transmission from the factory can set you back anywhere from $4,000 to $7,000. Of course, this number can vary depending on the make and model of your vehicle.

In many cases, though, you might not need a full replacement. If you’re open to exploring other options that can save you some cash, then a scrap yard might be your new best friend. As you might expect, buying a used gearbox from a scrap yard can be significantly cheaper.

Here’s a quick overview of the prices you can expect for a new gearbox and one from a scrap yard in a table for your convenience:

Gearbox Type Price Range
New Gearbox $4,000 – $7,000
Scrap Yard (Used) Gearbox $1,000 – $3,500

How Much Does It Cost to Replace Gearboxes?

For most cars, the average cost of a gearbox replacement typically falls between $900 and $1,200. This includes labor costs estimated to be between $160 and $210, while the parts themselves range from $750 to $950.

Now, if you own a four-wheel drive Pickup, the cost for a gearbox replacement can be a bit steeper. The average range for this specific vehicle is about $2,000 and $6,000, with labor costs running between $1000 and $1500, and parts prices ranging from $1,800 to $4,500.

What Happens When A Gearbox Breaks?

When your gearbox breaks, you might notice strange noises or difficulty shifting gears. If you experience these issues, it’s important to address them immediately, as continuing to drive with a faulty gearbox can lead to more severe problems down the road.

If a transmission seal breaks, it can cause leaking transmission fluid, which can result in serious issues. Your car’s performance will likely suffer, and you may even find it impossible to drive.

Unfortunately, you cannot continue driving with a faulty gearbox. If you suspect an issue with your gearbox, it’s best to get your car to a mechanic as soon as possible to avoid causing further damage. Ignoring the issue may result in complete gearbox failure, leaving your vehicle immobile. In this case, your only option would be to replace the entire gearbox, which can be quite costly.

Remember, being proactive and addressing any gearbox issues early can save you time, money, and stress. A well-maintained gearbox is essential for a smooth and safe driving experience.

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