Finding a replacement car part sounds simple until you discover that the same vehicle can have several different engines, gearboxes, differentials, fuel systems or electronic components.

A part may look almost identical to another component but still be completely unsuitable for your vehicle.

This is particularly important when buying used engines, automatic gearboxes, CVT transmissions, differentials, transfer boxes, fuel-injection pumps and other specialist 4x4 parts.

So how do you make sure you order the correct part?

The answer is accurate identification.

Your vehicle registration number, VIN or chassis number, engine code, gearbox code, OEM part number and photographs of the existing component can all help identify the correct replacement.

In this guide, we explain what each piece of information means, where to find it and why it matters when buying used or remanufactured automotive parts.

Why Is Correct Car-Part Identification So Important?

Modern vehicles can have many different versions of the same model.

For example, one vehicle model may be available with:

• Several engine sizes
• Different engine codes
• Manual or automatic transmissions
• Different automatic gearbox versions
• Different differential ratios
• Two-wheel or four-wheel drive
• Different electronic systems
• Different production years
• Different trim levels
• Different markets and specifications

As a result, searching for:

"Toyota Hilux gearbox"

may not provide enough information to identify the correct component.

You may need to know the exact vehicle specification and transmission code.

The same principle applies to engines, differentials, transfer boxes and fuel-injection systems.

What Information Do You Need to Find the Correct Car Part?

When contacting a specialist used-parts supplier, try to provide as much of the following information as possible:

1. Vehicle registration number

The registration number can help identify the vehicle's basic specification.

2. VIN or chassis number

The VIN provides much more detailed vehicle identification information.

3. Make and model

For example:

• Toyota Hilux
• Toyota Land Cruiser
• Nissan Navara
• Mitsubishi L200
• Mazda BT-50

4. Vehicle year

The production year can be important because specifications can change during a model's production.

5. Engine code

The engine code can distinguish between different engines used in the same model.

6. Gearbox or transmission code

This is particularly important when sourcing automatic or CVT transmissions.

7. OEM or manufacturer part number

This can be one of the most useful pieces of information available.

8. Photographs

Clear photographs of the existing component, identification labels and part numbers can help a specialist confirm compatibility.

What Is a VIN Number?

VIN stands for Vehicle Identification Number.

It is a unique identification number assigned to an individual vehicle.

A VIN can contain information associated with the vehicle's manufacturer, model, specification and production.

For parts identification, the VIN can be particularly useful because it identifies the specific vehicle, rather than simply identifying the model family.

For example, two vehicles can both be called a Toyota Hilux while having different engines or transmission specifications.

The VIN helps narrow down the exact vehicle.

What Is a Chassis Number?

The term chassis number is commonly used in the automotive industry to refer to a vehicle identification number or manufacturer-specific vehicle identification reference.

Depending on the manufacturer and market, you may see references to:

• VIN
• Chassis number
• Frame number
• Vehicle identification number

When contacting a specialist supplier, provide the complete number exactly as it appears on the vehicle documentation or identification plate.

For some Japanese vehicles, the chassis/frame reference can be particularly useful when identifying specialist drivetrain components.

Can I Find a Car Part Using My Registration Number?

Often, a UK registration number can provide useful information about a vehicle.

However, the registration number should not always be treated as the final confirmation that a particular component will fit.

This is especially important for specialist components.

A vehicle can have different components depending on:

• Engine
• Transmission
• Production date
• Drivetrain
• Factory specification
• Market
• Optional equipment
• Previous modifications

For expensive components such as engines and gearboxes, additional identification is strongly recommended.

Providing the registration number plus the VIN/chassis number and existing part number where available gives a specialist much more information to work with.

What Is an OEM Part Number?

OEM means Original Equipment Manufacturer.

An OEM part number is a manufacturer's identification number assigned to a particular component or specification.

The number may appear on:

• A label
• Metal plate
• Sticker
• Stamped component
• Plastic housing
• Electronic module
• Engine component
• Gearbox casing

It may look something like:

12345-67890

or contain letters and numbers in another manufacturer-specific format.

The exact format varies between manufacturers.

Why Is the OEM Number So Important?

The OEM number can identify the specific component, rather than simply the vehicle it came from.

This can be extremely useful when sourcing:

• Automatic gearboxes
• CVT transmissions
• Differentials
• Transfer boxes
• Fuel-injection pumps
• ECUs
• Electronic control modules
• Turbochargers
• Engines
• Steering components

However, an OEM number should still be checked against the vehicle application.

A part number is valuable evidence, but correct identification should consider the complete application.

Where Can I Find the Part Number?

The location depends on the component.

You may find a part number:

On the engine

Look for identification plates, stickers, stamped numbers or manufacturer's markings.

On a gearbox

The transmission casing may have a stamped or attached identification plate.

On a differential

The housing, identification plate or manufacturer's markings may provide useful information.

On a fuel-injection pump

The pump may have a manufacturer's identification plate containing several numbers.

On an electronic module

Look for a label containing the manufacturer number, OEM number and other identification codes.

If you cannot locate the number, take clear photographs of the component from several angles.

A specialist supplier may be able to use those photographs together with your vehicle information to help identify the component.

What Is an Engine Code?

An engine code identifies a particular engine family or specification.

For example, Toyota vehicles can use engine codes such as:

• 1KD-FTV
• 1KZ-TE

Different engine codes can have major differences in:

• Fuel system
• Turbocharger
• Electronics
• Sensors
• ECU
• Mounting
• Ancillary components
• Power output
• Emissions specification

This is why simply saying:

"I need a Toyota Hilux engine"

may not be enough information.

The engine code is much more useful.

Why Does the Gearbox Code Matter?

The gearbox code can be just as important as the engine code.

A vehicle may have multiple transmission options depending on its engine, year and specification.

For automatic and CVT transmissions, the exact transmission code can help distinguish between different internal and electronic configurations.

Before ordering a used automatic gearbox, provide:

• Vehicle registration
• VIN/chassis number
• Engine code
• Gearbox code
• Existing gearbox part number
• Photographs where possible

This can significantly reduce the risk of ordering an incompatible transmission.

How Do I Identify a Used Differential?

Differentials require particular care because gear ratio and specification are critical.

For example, a differential marked:

10 × 41

has a ratio of:

4.10:1

while another differential may have a different ratio.

Two differential housings can appear very similar while having different internal gearing.

When identifying a used differential, check:

• Front or rear
• Gear ratio
• Differential type
• Open or limited-slip differential
• E-Locker specification
• Number of splines
• Housing configuration
• OEM number
• Vehicle application

This is particularly important with 4x4 vehicles.

How Do I Identify a Toyota Hilux Part?

Toyota Hilux vehicles have been produced with numerous engine, transmission and drivetrain configurations.

When looking for a replacement Hilux component, provide as much information as possible.

Ideally include:

Registration + VIN/chassis number + engine code + gearbox code + OEM part number + photographs.

For drivetrain components such as differentials and transfer boxes, also provide the existing component's identification markings and specification.

This is much more reliable than searching for a component based only on:

"Toyota Hilux parts."

How Do I Identify a Toyota Land Cruiser Part?

Toyota Land Cruiser models have also been produced in numerous configurations and generations.

When looking for a replacement Land Cruiser:

1. Identify the exact model.
2. Confirm the production year.
3. Provide the VIN/chassis number.
4. Confirm the engine code.
5. Confirm the transmission.
6. Provide the existing component's part number.
7. Take photographs of the component.

This information is particularly important for:

• Differentials
• Transfer boxes
• Automatic transmissions
• Engines
• Fuel-injection systems
• Electronic modules

Why Can Two Parts Look the Same But Not Fit?

This is one of the most common problems when buying automotive components.

Two parts can have:

• Similar housings
• Similar connectors
• Similar dimensions
• Similar mounting points
• Similar appearance

but still have different internal specifications.

For example, a transmission may use different:

• Gear ratios
• Solenoids
• Valve bodies
• Sensors
• Electronic controls
• Internal components

Similarly, differentials can have different ratios or locking systems.

Never rely on appearance alone when purchasing a high-value automotive component.

Are Photographs Useful for Identifying Car Parts?

Yes.

Good photographs can provide valuable additional information.

When photographing a component, take:

A full photograph

Show the entire part.

Identification-label photograph

Make the part number completely readable.

Connector photograph

For electronic components, show the electrical connectors.

Mounting-point photograph

Show the mounting holes and brackets.

Close-up photographs

Photograph any stamped or engraved numbers.

Multiple angles

Photograph the component from several sides.

Avoid blurry photographs and make sure the identification label is in focus.

What Should I Send a Parts Specialist?

If you are asking PartsBook or another specialist to help identify a replacement component, the following information is ideal:

Vehicle:

• Make
• Model
• Year
• Registration

Vehicle identification:

• VIN
• Chassis/frame number

Engine:

• Engine size
• Engine code

Transmission:

• Manual/automatic/CVT
• Gearbox code

Component:

• OEM number
• Manufacturer number
• Component code

Photos:

• Full component
• Identification plate
• Stamped numbers
• Connectors
• Mounting points

The more information you provide, the easier it is to determine exactly which component you need.

What If I Don't Have the OEM Part Number?

Do not worry.

Not every vehicle owner has access to the part number.

A specialist may still be able to help using:

• Registration number
• VIN/chassis number
• Vehicle model
• Year
• Engine code
• Gearbox code
• Photographs
• Existing component details

If the part is already removed from the vehicle, photograph every identification mark before disposing of or returning the old component.

Should I Send the Old Part to the Supplier?

Sometimes the physical component can provide valuable identification information, particularly when several versions exist.

However, whether a component should be sent anywhere depends on the supplier's process.

Always contact the supplier first rather than sending an automotive component without agreement.

What Happens If I Order the Wrong Part?

An incorrect part can create unnecessary:

• Delivery costs
• Installation costs
• Vehicle downtime
• Return arrangements
• Labour costs
• Diagnostic work

This is why identification should happen before the order, not after the component has been delivered.

For expensive parts such as engines, gearboxes and differentials, spending a few extra minutes confirming the specification can save significant time and expense.

Why Specialist Used-Part Suppliers Matter

Buying a used automotive component is different from buying a generic consumer product.

A specialist supplier needs to understand:

• Vehicle applications
• Engine codes
• Transmission codes
• OEM numbers
• Differential ratios
• Drivetrain configurations
• Component condition
• Compatibility
• Installation requirements

This is particularly important for 4x4 components, where drivetrain specifications can vary considerably between vehicles that appear very similar.

What Is the Best Way to Find the Correct Used Car Part?

The safest approach is to provide multiple identification points rather than relying on one piece of information.

A useful identification checklist is:

Vehicle identification

Registration + VIN/chassis number

Vehicle specification

Model + year + engine code + transmission

Component identification

OEM/part number + manufacturer's number

Visual confirmation

Clear photographs

Specialist verification

Have the application checked before purchasing.

This combination gives the supplier the best possible information to identify the correct replacement.

PartsBook: Specialist Used & Remanufactured Automotive Parts

PartsBook.co.uk specialises in used and remanufactured automotive components, particularly specialist 4x4 parts.

The range includes components such as:

• Used engines
• Automatic gearboxes
• CVT transmissions
• Differentials
• Transfer boxes
• Fuel-injection pumps
• Turbochargers
• Electronic automotive components
• Other specialist vehicle components

If you are unsure which part you need, provide as much identification information as possible before ordering.

Registration, VIN/chassis number, engine code, gearbox code, OEM number and photographs can all help establish the correct component.

Frequently Asked Questions

Can I find a used car part using my registration number?

A registration number can help identify a vehicle, but it may not be sufficient to confirm a specialist component. For expensive parts, provide the VIN/chassis number and component identification information as well.

Is the VIN better than the registration number for finding car parts?

The VIN identifies the individual vehicle and can provide more detailed identification information. However, the exact component's OEM number or code can still be important.

What is an OEM part number?

An OEM part number is a manufacturer's identification number used to identify a specific component or specification.

Where can I find my car's OEM part number?

Depending on the component, it may be printed on a label, stamped into the component, shown on an identification plate or marked on an electronic module.

Why do I need my engine code?

The same vehicle model can use different engines. The engine code helps identify the specific engine specification.

Why do I need a gearbox code?

A vehicle may have multiple transmission options. The gearbox code helps identify the exact transmission variant.

Can photographs help identify a used car part?

Yes. Clear photographs of the complete component, identification labels, numbers, connectors and mounting points can provide useful identification information.

Can two identical-looking car parts be different?

Yes. Components can look almost identical while having different internal specifications, ratios, electronics or applications.

What information should I provide when buying a used gearbox?

Ideally provide the vehicle registration, VIN/chassis number, engine code, gearbox code, OEM part number and photographs of the existing gearbox.

What information do I need to buy a used differential?

Provide the vehicle details, VIN/chassis number, front/rear position, differential ratio, differential type, OEM number and photographs or identification markings where available.

What if I cannot find my part number?

Contact a specialist with your vehicle registration, VIN/chassis number, engine and gearbox information and clear photographs of the component. They may be able to establish the correct application from the available information.

How can I avoid buying the wrong used car part?

Do not rely solely on the vehicle model or appearance of the component. Confirm the vehicle specification and match the component using the appropriate OEM number, code, ratio or other technical identification information before ordering.