The Komatsu D-Series covers bulldozers for very different jobs, from smaller grading and earthmoving work to heavy quarry, land-clearing and production applications. A used buyer should therefore ask more than “Is this a Komatsu D-Series machine?” The better question is: “Which D-Series model, generation and undercarriage configuration matches my ground conditions and workload?”
Start with machine size, blade type, track width, ground pressure and required production. Then confirm the complete model designation, including suffixes such as EX, PX or i. Used buyers should inspect the undercarriage, blade, final drives, hydraulics, engine, steering or transmission system, frame and any ripper equipment. This guide explains how overseas buyers can compare representative Komatsu D-Series bulldozers before purchasing a machine from Japan.
The D-Series Covers Several Machine Classes
Komatsu uses the D designation across a broad bulldozer range.
Representative current or recent models include:
- D39
- D51
- D61
- D65
- D71
- D85
- D155
These machines differ greatly in horsepower, operating weight, blade capacity, track system and intended application.
For example, Komatsu currently classifies the D39 and D51 as small dozers, the D65 as a mid-size dozer, and the D85 and D155 as large dozers in some markets.
Specifications vary by model year and configuration. Exact specifications should be confirmed for each individual machine.
A Practical D-Series Size Guide
| Model Example | General Position | Typical Buyer Direction |
|---|---|---|
| D39 | Small dozer | Grading, site preparation, road work, lighter earthmoving |
| D51 | Small dozer | General construction, highway work, grading, moderate earthmoving |
| D65 | Mid-size dozer | Heavy construction, land development, quarry support, larger earthmoving |
| D85 | Large dozer | Heavy earthmoving, quarry, soft-ground production depending on configuration |
| D155 | Large production dozer | Large-scale earthmoving, ripping, quarry and heavy-duty production |
This table is a general buying direction rather than an official worldwide classification for every generation.
D39: A Smaller D-Series Option
The D39 is one of the smaller Komatsu bulldozers buyers may encounter in Japan.
Current Komatsu D39PX-24 specifications include:
- Net engine output: 78 kW / 105 HP
- Operating weight: 10,350 kg
- Blade capacity: 2.4 m³
This size direction can suit:
- General grading
- Road construction
- Small to medium earthmoving projects
- Site preparation
- Utility and infrastructure work
Its smaller size can also simplify local transport compared with larger production dozers.
D39EX vs D39PX: Same Power, Different Ground Strategy
The EX and PX suffixes matter.
Current Komatsu D39EX-24 and D39PX-24 machines use the same listed 78 kW net engine output, but their undercarriages differ.
The D39EX-24 uses a narrower standard shoe, while the D39PX-24 uses wider shoes and lower ground pressure.
| Current Example | D39EX-24 | D39PX-24 |
|---|---|---|
| Net Power | 78 kW | 78 kW |
| Standard Shoe Width | 510 mm | 635–700 mm depending on specification |
| Ground Pressure | Higher | Lower |
| Direction to Consider | Firm ground and general work | Softer ground where flotation matters |
The practical lesson is simple:
Do not select a dozer only by horsepower or model number. Confirm the full undercarriage configuration.
PX Usually Deserves Attention for Soft Ground
Komatsu uses PX configurations on several dozer families.
PX versions commonly use wider shoes and lower ground pressure than corresponding EX models.
This can be useful in:
- Soft soil
- Wet construction sites
- Loose ground
- Ground where flotation matters
However, wider tracks are not automatically better for every application.
Firm, rocky or abrasive ground can favor another configuration depending on the work.
D51: A Flexible Construction Dozer
The D51 class is a step above the D39 and remains highly relevant for contractors.
Current D51PX-24 specifications include:
- Net engine output: 98 kW / 131 HP
- Operating weight: 14,180 kg
- Blade capacity: 3.36 m³
- Standard shoe width: 710 mm
Komatsu positions this machine for applications ranging from golf-course construction to highway projects and grading work.
This class can suit buyers who need more pushing capability than a D39 but do not require a large production dozer.
D51EX and D51PX Should Not Be Treated as Identical
Current D51EX-24 and D51PX-24 models use the same listed 98 kW net engine output, but their undercarriage and blade specifications differ.
The PX model has a wider standard track setup and lower ground pressure.
Komatsu also lists a larger blade capacity on the D51PX-24 than the D51EX-24 in the current market specification.
This means buyers should compare:
- Shoe width
- Ground pressure
- Blade capacity
- Operating weight
- Actual ground conditions
What Does the “i” Mean on Some D-Series Machines?
Komatsu offers Intelligent Machine Control versions of some dozers, identified by model designations such as D39PXi-24 and D51PXi-24.
These machines integrate machine-control technology for grading and automated blade functions.
For example, current D51PXi-24 information includes features such as:
- Integrated machine control
- Proactive dozing control
- Automatic spreading functions
- Grade-control support
For a used overseas buyer, this can be valuable when digital grading is part of the business.
However, it also creates an additional question:
Can the destination market support the electronic and machine-control system?
Newer Technology Is Useful Only If You Can Support It
An i-series machine may offer more automation, but buyers should confirm:
- Display and monitor condition
- Sensors
- Wiring
- Machine-control components
- Local diagnostic capability
- Software or service support
If advanced machine control is not needed for your work, an older mechanical or conventional electronic machine may still be practical.
D65: A Mid-Size Workhorse
The D65 moves into a larger and more productive class.
Current D65EX-18 specifications include:
- Engine output: 162 kW / 217 HP
- Operating weight: approximately 20,697–22,133 kg depending on configuration
- Blade capacity: 5.6 m³
Komatsu positions the D65EX-18 as an all-around mid-size dozer for heavy work.
This class can make sense for:
- Large construction projects
- Road development
- Quarry support
- Land clearing
- Heavy earthmoving
D65PX: Lower Ground Pressure for Heavy Work
The D65PX-18 uses a wider low-ground-pressure track setup.
Komatsu specifically positions it for heavy loads in soft or wet conditions.
Current D65PX-18 specifications list:
- Engine output: 162 kW / 217 HP
- Operating weight: approximately 21,974–23,569 kg
- Blade capacity: 3.7 m³ in the current listed configuration
The different blade capacity compared with the EX model is another reminder that configuration matters.
Do not assume the PX is simply an EX with wider tracks.
Blade Type Is a Major D-Series Buying Point
Komatsu offers different blades across the D-Series.
Depending on model and configuration, buyers may encounter:
- Power Angle Tilt blade
- Straight blade
- Semi-U blade
- Sigmadozer blade
- Full-U blade on some larger machines
Each blade changes how the machine handles material.
Consider a PAT Blade When...
- Grading is important.
- You need angle adjustment.
- Road and site-finishing work are common.
Consider a Semi-U or Larger Production Blade When...
- You need to push larger volumes.
- Production earthmoving matters more than fine grading.
- The jobsite has enough room for a wider blade.
Confirm the exact blade installed on the used machine rather than relying on a brochure image.
D85: A Large Dozer for Higher Production
The D85 class moves into larger earthmoving and production work.
Current D85PX-18 specifications list:
- Engine output: 197 kW / 264 HP
- Operating weight: 29,300 kg
- Blade capacity: 5.9 m³
Komatsu positions the PX version for soft-ground work requiring flotation.
The D85EX-18 belongs to the same family but follows a different track and ground-pressure direction.
Buyers moving into this size class should give more attention to:
- Transport cost
- Undercarriage cost
- Fuel consumption
- Blade wear
- Final-drive condition
- Ripper requirement
D155: Large-Scale Production and Ripping
The D155AX-8 represents a much larger class.
Current Komatsu specifications list:
- Engine output: 264 kW / 354 HP
- Operating weight: 40,506 kg
- Blade capacity: 9.4–11.9 m³ depending on blade
Komatsu offers blade choices including Semi-U and Full-U on this class.
This size is intended for heavy production rather than ordinary small construction work.
Consider a D155-class machine only when your project can use the production capacity and support the higher ownership and transport cost.
EX vs PX vs AX: Do Not Ignore the Suffix
Komatsu D-Series suffixes can reflect major differences.
They may affect:
- Track width
- Ground pressure
- Blade options
- Undercarriage layout
- Machine weight
- Intended application
Therefore, “D65” is not enough information for a purchase decision.
Ask for the complete model such as D65EX-18 or D65PX-18.
The Undercarriage Can Decide Whether the Machine Is Good Value
Bulldozer undercarriage condition should be one of the first used-machine checks.
Inspect:
- Track shoes
- Grouser height
- Links
- Pins and bushings
- Rollers
- Idlers
- Sprockets
- Track frames
- Track tension
Some current Komatsu models use the PLUS, or Parallel Link Undercarriage System.
Komatsu describes this system as designed to improve wear life by using components such as rotating bushings.
On a used machine, the system type should be identified before parts or replacement costs are estimated.
Inspect the Sprockets, Rollers and Idlers
Look for:
- Hooked or sharp sprocket teeth
- Roller leakage
- Seized rollers
- Idler wear
- Uneven wear between left and right tracks
- Damaged track hardware
Undercarriage wear should be evaluated as a complete system rather than as isolated parts.
Inspect the Final Drives
The final drives transfer power to the tracks.
Check:
- Oil leaks
- Housing damage
- Abnormal noise
- Uneven travel response
- Available oil-service information
The D39-24 specification, for example, uses in-shoe axial-piston travel motors with planetary reduction.
Older D-Series generations can use different drive arrangements, so do not assume every model has the same system.
Understand the Drive System Before Testing
Smaller current Komatsu dozers such as the D39-24 use electronically controlled hydrostatic transmission.
Larger machines such as the D65, D85 and D155 use different powertrain designs, including torque-converter and transmission systems.
This matters during inspection.
Test:
- Forward travel
- Reverse travel
- Steering response
- Counter-rotation where supported
- Shift behavior
- Unusual delay
- Warning codes
Blade Wear Can Reveal Previous Work
Inspect:
- Cutting edge
- End bits
- Blade face
- Side structure
- Push arms
- Hydraulic cylinders
- Repair welding
Heavy quarry or abrasive work can wear blade components quickly.
Fresh paint does not prove that the blade has substantial remaining life.
Check the Ripper Where Fitted
Many larger D-Series machines can use rear-mounted rippers.
A ripper can be valuable for:
- Hard ground
- Rock
- Compacted material
- Land clearing
If fitted, inspect:
- Shanks
- Tips
- Pins
- Mounting beam
- Hydraulic cylinders
- Cracks and repairs
Also confirm whether the ripper is actually included in the sale.
Operating Hours Need Context
Do not compare two D-Series dozers only by hour meter.
Review hours together with:
- Undercarriage wear
- Previous application
- Blade condition
- Final-drive condition
- Engine condition
- Maintenance information
- Ripper use
A 5,000-hour machine used mainly for grading can have a very different wear profile from a 5,000-hour machine used in rock pushing.
Check the Engine and Cooling System
Inspect:
- Cold starting where possible
- Smoke
- Oil leaks
- Coolant leaks
- Abnormal noise
- Warning indicators
- Radiator condition
- Cooling fan
Some newer Komatsu models use reversing hydraulic fans to help clear the cooling package.
Older generations may use different systems.
Emissions Equipment Differs by Generation and Market
Current North American D39-24 specifications use an EPA Tier 4 Final-certified engine and a DEF system.
That does not mean every used Japanese D39 or other D-Series bulldozer has the same emissions equipment.
Before buying a newer machine, confirm:
- Exact engine specification
- Emissions system
- Fuel requirements
- DEF or other fluid requirements where applicable
- Local diagnostic capability
Market and generation differences are important.
Parts Support Should Influence Model Choice
A larger or newer D-Series bulldozer may provide more performance, but the machine still needs local support after export.
Check availability of:
- Filters
- Track parts
- Rollers and idlers
- Final-drive parts
- Hydraulic seals
- Blade wear parts
- Engine parts
- Electronic components
A model already familiar to local workshops may be easier to operate economically than a technically newer machine with limited support.
Which D-Series Class Should You Consider?
| Main Requirement | Direction to Consider |
|---|---|
| General grading and smaller construction | D39 class |
| Road work and moderate earthmoving | D51 class |
| Heavy construction and land development | D65 class |
| Large earthmoving and soft-ground production | D85 class depending on configuration |
| Heavy production, large-scale pushing and ripping | D155 class |
Use this only as a starting point.
Actual ground conditions, production target, blade type and transport limits should decide the machine.
A Practical Komatsu D-Series Buyer Checklist
- Model: Confirm the complete D-Series designation.
- Suffix: Identify EX, PX, AX, i or other configuration.
- Serial Number: Confirm the individual machine identity.
- Ground: Decide whether the track setup matches firm or soft conditions.
- Blade: Confirm type, capacity and hydraulic functions.
- Undercarriage: Inspect tracks, links, bushings, rollers, idlers and sprockets.
- Track Tension: Compare condition with the correct manufacturer specification.
- Final Drives: Check leaks, noise and travel response.
- Drive System: Identify HST, transmission or torque-converter design for that generation.
- Hydraulics: Test blade and ripper functions where possible.
- Ripper: Check wear and confirm inclusion if required.
- Engine: Review starting, smoke, leaks and warnings.
- Cooling: Inspect radiator and fan condition.
- Electronics: Check displays and machine-control systems on newer models.
- Hours: Compare the hour meter with actual wear and previous use.
- Parts: Confirm local service and parts availability.
- Transport: Confirm weight, blade width and overall dimensions.
Buying a Used Komatsu D-Series Bulldozer from Japan
Japanese used machinery can include Komatsu D-Series bulldozers from several generations, size classes and track configurations.
You can check current Japanese used machinery available at EVERYCAR.jp. Inventory changes regularly, so a specific D-Series model should not be assumed to remain available.
When making an inquiry, useful details include the preferred D-Series model or approximate machine size, ground conditions, blade requirement, ripper requirement, budget and destination.
For broader information about bulldozer inspection, operating hours, hydraulics, attachments and international purchasing, visit the Japanese Used Machinery & Heavy Equipment Guide.
Choose the D-Series Configuration Before Comparing Individual Machines
A Komatsu D-Series bulldozer should not be selected only by model number or horsepower.
First determine the machine class that matches your work.
Then choose the correct undercarriage direction, blade and ground-pressure configuration.
After that, evaluate the individual used machine by undercarriage wear, final drives, hydraulics, blade, engine, ripper, operating hours and maintenance information.
If you are looking for a used Komatsu D-Series bulldozer from Japan, you can contact EVERY with your preferred model or size, intended work, ground conditions, blade or ripper requirements, budget and destination. Exact specifications, configuration and condition should be confirmed for each individual machine before purchase.
Browse Reliable Used Trucks & Buses from Japan
Carefully selected vehicles ready for export worldwide
Search 100,000+ Dealer Stock Vehicles from Japan
Access a wide selection of vehicles from Japanese dealers nationwide. Updated daily.
