Is a Gearbox the Same as a Transmission?

Generally, no: in most automotive contexts, “transmission” refers to the entire mechanism that manages power and gear changes, while “gearbox” usually means the set of gears (and its housing) within that system. However, in British and some Commonwealth usage, “gearbox” is often used interchangeably with “transmission,” so context and region matter.

What Each Term Usually Means

In American automotive English, “transmission” is the broader term. It typically includes the gearset, clutches or torque converter, hydraulic or electronic controls, and sometimes the differential when integrated into a single unit (a transaxle). The “gearbox” is more specific: it’s the mechanical gearset and casing that provide the ratios.

In engineering and machinery beyond cars, a “gearbox” can describe any gear reduction unit that changes speed/torque—for example, in industrial equipment or wind turbines. In those contexts, “transmission” may refer to a larger powertrain system that incorporates the gearbox plus other components.

Regional Usage and Everyday Language

How people talk about these parts varies by region and vehicle category. The points below explain how the terms commonly differ in practice.

• United States and Canada: “Transmission” is standard for the whole assembly; “gearbox” is used less often and usually means the gearset itself, especially in manuals.
• United Kingdom, Ireland, Australia, New Zealand: “Gearbox” is frequently used where North Americans would say “transmission,” particularly for manual cars.
• Motorcycles: Riders often say “gearbox” for the bike’s internal gearset; “transmission” may be used more formally or in service manuals.
• Motorsport and heavy equipment: “Gearbox” is widely used for the gear unit; “transmission” can refer to the broader driveline system.

Because the language varies, it’s best to clarify what is meant—especially when discussing repairs, warranties, or parts ordering.

Key Differences at a Glance

These distinctions highlight when the terms overlap and when they don’t.

• Scope: Transmission = entire shifting and power-transfer system; Gearbox = mechanical gearset and housing.
• Components: Transmissions often include clutches/torque converters and control modules; Gearboxes focus on gears, shafts, bearings, and selectors.
• Integration: In many front-wheel-drive cars, the transmission and differential are combined into a transaxle; the gearbox is one part of that unit.
• Language: In British/Commonwealth contexts, “gearbox” can mean the whole transmission; in North America, it usually does not.

While casual conversation may blur the terms, these differences matter in technical documentation and service procedures.

Types and Examples

Below is a quick guide to common transmission designs and how the term “gearbox” applies within each.

1. Manual (MT): Driver-operated clutch with a mechanical gearset. The gearbox is the heart of the system; many English speakers call the whole unit a gearbox.
2. Automatic (AT): Uses a torque converter and planetary gearsets with hydraulic/electronic controls. The gearbox refers to the planetary gearsets; the transmission includes converter and control systems.
3. Continuously Variable (CVT): Employs a belt/chain and variable pulleys (or toroidal rollers). The “gearbox” is the variator unit; the transmission includes the hydraulic/electronic control system.
4. Dual-Clutch (DCT): Two clutches and two sub-gearsets operated automatically. The gearbox is the paired gearsets; the transmission includes clutches and mechatronics.
5. Automated Manual (AMT): A manual gearbox with automated clutch/shift actuators. The gearbox is manual; actuators and controls make it a transmission.
6. Hybrid eCVT (planetary-split): Uses a planetary gearset to blend engine and motor speeds (e.g., Toyota/Lexus HSD). The gearbox is the planetary set; the transmission includes motors and controls.
7. Electric vehicle (EV) reduction drive: Usually a single-speed reduction gearset. It’s often called both a transmission and a gearbox; mechanically it’s a gearbox, functionally it serves as the transmission.

Across these designs, the gearbox is the mechanical core, while the transmission encompasses the full operating system that manages ratio changes and power flow.

Electric Vehicles: A Special Case

Most EVs use a single-speed reduction gearbox that takes the high-speed output of the electric motor and reduces it to wheel-speed. Automakers frequently label this whole unit a “transmission” for consumer familiarity, even though it contains no multi-ratio shifting in normal operation.

Notable exceptions exist: the Porsche Taycan uses a two-speed rear transmission to improve both acceleration and efficiency at highway speeds. Hybrids with eCVTs rely on planetary gearsets and electric motors to vary effective ratios without traditional stepped gears.

Practical Implications for Owners

If you’re scheduling service or diagnosing issues, it helps to know what you’re referring to. The list below outlines common scenarios and terminology tips.

• Repair orders: Saying “transmission problem” usually covers any shifting, slipping, or engagement issue; “gearbox noise” suggests gear/bearing wear inside the case.
• Parts and costs: Transmission replacements often include clutches/torque converter and control units; gearbox-specific repairs target gears, synchros, shafts, or bearings.
• Diagnostics: Fluid type and service procedures differ across MT, AT, CVT, DCT, and EV units; using the correct term helps a shop quote accurately.
• Transaxles: On many FWD cars, the transmission includes the differential; failures there can mimic axle or wheel-bearing issues.

Clear terminology can save time and money by directing technicians to the right components and procedures from the start.

Related Terms You May Hear

These adjacent terms often appear alongside gearbox/transmission and can clarify what’s included.

• Transaxle: A transmission with an integrated differential (common in FWD and some RWD/mid-engine cars).
• Final drive: The last gear reduction before the wheels; sometimes integrated with the transmission, sometimes separate.
• Mechatronics/valve body: The control unit for automatics and DCTs; manages hydraulic pressure and shift logic.
• Clutch/torque converter: Interfaces that connect or modulate engine power to the gearset in manual and automatic systems.

Understanding these terms helps pinpoint which part of the drivetrain is being discussed or serviced.

Bottom Line

A gearbox is the mechanical gearset. A transmission is the complete system that changes ratios and manages power delivery. In some regions—especially the UK—people use “gearbox” to mean the entire transmission. In technical contexts and in North America, the distinction is sharper.

Summary

No, a gearbox is not always the same as a transmission. The gearbox is the gearset inside the transmission, while the transmission includes additional components such as clutches or a torque converter, controls, and sometimes the differential. Regional language can blur the terms, and EVs add nuance since their single-speed reduction units are both mechanically a gearbox and functionally the vehicle’s transmission.

Does an automatic transmission have a gearbox?

An automatic transmission (AT) or automatic gearbox is a multi-speed transmission used in motor vehicles that does not require any input from the driver to change forward gears under normal driving conditions.

How much does it cost to fix a gearbox?

Gearbox repair costs vary significantly, ranging from hundreds of dollars for minor issues (like a new clutch or seal) to thousands of dollars for a full replacement or rebuild. The type of gearbox (manual vs. automatic, or even a steering gearbox), the vehicle’s make and model, the severity of the damage, and the chosen repair shop all influence the final price. For a precise estimate, it’s best to get a professional diagnosis and multiple quotes from reputable mechanics or specialty transmission shops.
 
Cost Breakdown

• Minor Repairs: Opens in new tabThese are the cheapest options and can range from $300 to $1,500 for a new clutch in a manual or minor internal fixes. 
• Major Repairs (Rebuilds): Opens in new tabRebuilding a gearbox to repair internal mechanical damage typically costs between $1,500 to $3,000, but can be as high as $2,000-$3,400 or more for a full overhaul. 
• Transmission Replacement: Opens in new tabReplacing the entire unit is one of the most expensive repairs, with costs ranging from $2,000 to $4,000 or more, depending on the vehicle. 
• Steering Gearbox: Opens in new tabReplacing a steering gearbox specifically can cost around $1,057 to $1,289, with parts accounting for the majority of the cost. 

Factors Influencing Cost

• Type of Gearbox: Automatic transmissions are generally more expensive to repair or replace than manual ones due to their complexity. 
• Vehicle Make and Model: Luxury or high-performance vehicles will have higher costs for both parts and specialized labor compared to common compact cars. 
• Severity of Damage: Minor issues like leaks or worn-out components are less expensive than extensive internal mechanical damage. 
• Type of Replacement: A remanufactured unit is a good middle-ground option, while a used/salvage unit is cheaper but riskier. 
• Labor Costs: Labor is a significant portion of the total cost and can vary based on the repair shop’s rates and location. 

Tips for Getting a Good Deal

• Shop Around: Get quotes from independent mechanics, dealerships, and specialty transmission shops to compare prices. 
• Consider a Reputable Remanufactured Unit: These offer a good balance of cost and quality, often with a warranty. 
• Check for Recalls or Extended Warranties: Some manufacturers cover certain gearbox failures under recalls or extended warranties. 

What’s the difference between a transmission and a gearbox?

A gearbox is the mechanical component that changes speed and torque, while a transmission is the complete system that uses the gearbox to transfer power from an engine to the wheels, including controls like clutches or torque converters. Think of it this way: a gearbox is like a specific tool, and the transmission is the entire toolkit that uses that tool to achieve the overall goal of moving the vehicle.
 
Gearbox

• What it is: A mechanism of gears, shafts, and other components. 
• What it does: Alters the speed and torque between the input and output shafts. 
• Where it’s found: In vehicles, but also in various other industrial and mechanical applications where power needs to be transmitted and modified. 

Transmission

• What it is: The entire assembly that controls power flow from the engine to the wheels. 
• What it includes: A gearbox, along with other necessary parts such as the clutch, torque converter, and electronic controls. 
• What it does: Manages the engine’s power, automatically or manually shifting gears to provide the right balance of speed and torque for different driving conditions. 
• Where it’s found: Primarily in vehicles. 

What is another name for a gearbox?

A transmission (also called a gearbox) is a mechanical device invented by Louis Renault (who founded Renault) which uses a gear set—two or more gears working together—to change the speed, direction of rotation, or torque multiplication/reduction in a machine.