• 20,749 lbs Operating Weight
  • 105 @2200 rpm Horsepower
  • 2.89 yd³ Blade Capacity


Need a great grading tractor with plenty of power and a cab your operators will fight over. You’ve found it with the D39EX-23. The super slant nose moves the coolers and hydraulic fan to the rear, the operator more forward and the result is a new way of balancing a dozer to make it an incredibly easy tractor to finish grade with. Add a more efficient, fully hydrostatic drivetrain for precise maneuverability and control, two working modes for more efficient work matching and fuel savings and fuel efficient Tier 4 interim engine technology and you have everything you want and need in a small dozer. Put your grade control system on it and you have a high speed yet very precise fine grading system.

D39EX-23 Walkaround  >


Daily Checks

All daily checks can be performed efficiently from the left side of the machine.

ECO Guidance

In order to support optimum operation, the following 4 recommendations are displayed to improve fuel saving operation:

    1) Avoid Excessive Engine Idling

    2) Use Economy Mode to Save Fuel

    3) Avoid Hydraulic Relief Pressure

    4) Avoid Overload

The operator can access the ECO guidance menu to check the Operation Records, Eco Guidance Records, and Average Fuel Consumption logs.

Electronic Controlled Hydraulic System (EPC) Blade Control Joystick

Blade control joystick uses the EPC valve and joystick, similar to the travel control joystick. EPC control combined with the highly reliable Komatsu hydraulic system enables superb fine control. A switch is now used to angle the PAT blade. A button to activate float is also provided.

Hydraulically-Driven Swing-up Fan

The D37-23 utilizes a swing-up fan with a gas strut-assisted lift locking system to provide easy access to the (side-by-side) radiator, oil cooler, and charge air cooler. The swing-up feature makes it easier to access cooling cores. The hydraulic fan can rotate in the reverse direction to help remove debris from cooler cores.

Modular Design

One of the design goals behind the creation of the D37 was to manufacture a more durable machine. This was achieved by reducing component complexity and using a strong modular design for increased serviceability and durability. Steel castings reduce the number of welds, improving C-frame rigidity and strength.

New HST Technology

The D39-23 incorporates new proprietary engine and hydrostatic transmission pump control technology to improve operational efficiency and reduce fuel consumption to levels lower than a conventional HST control system can obtain. This Komatsu exclusive feature reduces fuel consumption by up to 10% in P mode in demanding working conditions and up to 20% in E mode under lighter load conditions as compared to the prior model.

Powerful turns under various work conditions are achieved with the new HST transmission, even under load. Counter-rotation is available for minimum turning radius, providing excellent maneuverability in tight spots.

Palm Command Control System (PCCS) Travel Joystick

Palm command travel joystick provides the operator with a relaxed posture and superb fine control. Transmission shifting is simplified with thumb push buttons.

Power Angle Tilt (PAT) Dozer With Adjustable Pitch

A Power Angle Tilt dozer blade with highly durable box-structure frame is available for the EX and PX machines. The hydraulic blade tilt and angling functions and manually adjustable blade pitch expand versatility and productivity in a variety of applications. This PAT dozer assembly is tested to stringent test standards.

Rear View Monitoring System

On the large LCD color monitor, the operator can view, through one camera, areas directly behind the machine. This camera can be synchronized with reverse operation.

Robust Guarding And Attachments

Komatsu offers a full guarding package to help protect your machine and operator in severe applications.

Secondary Engine Shutdown Switch

A new secondary switch has been added, at the side of the front console, to shut down the engine.

Selectable Working Mode

Working mode E is for general dozing applications with adequate speed and power while reducing fuel consumption and CO2. Working mode P is aimed at powerful operation and maximum production. The working mode is easily switched on the monitor panel, depending on the work at hand.

E mode (Economy mode)

With E mode, the engine outputs enough power for most general dozing applications without delivering unnecessary power. This mode allows for energy saving operation and is suitable for work on ground where the machine may experience shoe slip or applications not requiring large power such as downhill dozing, leveling and light-load work.

P mode (Power mode)

With P mode, the engine outputs its full power, allowing the machine to perform large production, heavy-load, or uphill work.

Single Pedal (Decelerator/Brake Pedal) to be operated for Speed Control, during Operation

Machine operation becomes simple because brake function has been integrated into decelerator pedal. Machine moving speed including/excluding engine speed can be controllable by using only one pedal of decelerator/brake pedal. Operation of pedal function can be changed by the mode selector switch.

Decelerator mode

The pedal can decelerate engine RPMS and vehicle travel speed. Normally can be used for all applications.

Brake mode

The pedal can decelerate vehicle travel speed, keeping high engine revolution. This mode can be helpful to keep work equipment controllability and/or force, even during braking.

Unrivaled Blade Visibility

The D39EX/PX-23 incorporates Komatsu’s super-slant nose design. Komatsu’s innovative design provides excellent blade visibility for improved machine control and increased efficiency and productivity.

Variable and New Customizable Quickshift Modes

The D39-23 offers two gearshift modes: Variable and the new Customizable Quick shift. Variable shift mode provides 20 incremental speed settings for the operator, while the new Customizable Quick shift provides 3 speed settings; all can be adjusted in the monitor to obtain the right speed for different operator preferences.



Model Komatsu SAA4D95LE-6*
Type 4-cycle, water-cooled, direct injection
Aspiration Variable flow turbocharged, air-to-air aftercooled
Number of cylinders 4
Bore x stroke 3.75" x 4.52" 95 mm x 115 mm
Piston displacement 199 in³ 3.26 ltr
Governor All-speed, electronic
SAE J1995 - Gross 107 HP 79 kW
ISO 9249 / SAE J1349 - Net 105 HP 78 kW
Rated rpm 2200 rpm
Fan drive type Hydraulic (reversible)
Lubrication system:
Method Gear pump, force lubrication
Filter Full-flow
*EPA Tier 4 Interim and EU stage 3B emissions certified

Final Drive

In-shoe mounted axial piston type travel motors with integrated two stage planetary gear reduction. Compact in-shoe mount reduces risk of damaged by debris. Bolt-on sprocket ring.

Hydraulic System

Closed-center Load Sensing System (CLSS) designed for precise and responsive control, and for efficient simultaneous operation.
Hydraulic control unit:
All spool control valves externally mounted remote to the hydraulic tank. Piston-type hydraulic pump with capacity (discharge flow) of 99 ltr/min 26 U.S. gal/min at rated engine rpm.
Relief valve setting 3,974 psi 27.4 MPa / 280 kg/cm²
Hydraulic cylinders Double-acting, piston type
Number of cylinders: Bore Bore
Blade lift / 2 3" 75 mm
Blade tilt / 1 3.6" 90 mm
Blade angle / 2 3.1" 80 mm
Blade pitch 1 adjustable linkage
Hydraulic oil capacity (refill):
Power angle tilt dozer 15.9 U.S. gal 60 ltr
Control valves:
3-spool control valve for Power Angle Tilt dozer
Blade lift Raise, hold, lower, and float
Blade tilt Right, hold, and left
Blade angle Right, hold, and left
Additional control valve required for ripper
Ripper lift Raise, hold and lower

Hydrostatic Transmission

Dual-path, hydrostatic transmission provides infinite speed changes up to 5.3 km/h / 8.5 mph. The variable capacity travel motors allow the operator to select the optimum speed to match specific jobs. Travel control lock lever and neutral switch.

Travel speed
(quick shift mode)*
1st0–2.1 mph
0–3.4 km/h
0–2.5 mph
0–4.1 km/h
2nd0–3.5 mph
0–5.6 km/h
0–4.0 mph
0–6.5 km/h
3rd0–5.3 mph
0–8.5 km/h
0–5.3 mph
0–8.5 km/h
Travel speed
(variable mode)
0–5.3 mph
0–8.5 km/h
0–5.3 mph
0–8.5 km/h
*Quick shift speeds are adjustable in the monitor.

Operating Weight (APROXIMATE)

Tractor weight:
Including ROPS cab, U frame for power angle tilt dozer, rated capacity of lubricant, coolant, full fuel tank, operator, and standard equipment.
ROPS cab 18,210 lb 8260 kg
Operating weight:
Including Power Angle Tilt dozer, ROPS cab, operator, standard equipment, rated capacity of lubricant, hydraulic control unit, coolant, and full fuel tank.
ROPS cab 20,749 lb 9410 kg

Service Refill Capacities

Coolant9.0 U.S. gal34 ltr
Fuel tank50.2 U.S. gal190 ltr
Engine oil2.9 U.S. gal11 ltr
Hydraulic tank15.8 U.S. gal60 ltr
Final drive (each side)0.9 U.S. gal3.5 ltr

Steering System

Palm Command Control System (PCCS) joystick control for all directional movements. Pushing the joystick forward results in forward machine travel, while pulling it rearward reverses the machine. Simply tilt the joystick to the left or right to make a turn. Tilting the joystick fully to the left or right activates counter-rotation.

Hydrostatic Transmission (HST) provides smooth powerful turns. Fully electronic control enables smooth control that can be adjusted in the monitor. The PCCS utilizes shift buttons to increase and decrease speed.

Minimum turning radius:87"2.2 m
As measured by track marks on the ground at pivot turn.


Suspension Rigid type
Track roller frame Monocoque, large section, durable construction
Rollers and idlers Lubricated track rollers
Sealed and lubricated track Track tension is easily adjusted with grease gun.
Number of track rollers (each side) 6
Type of shoes (standard) Single grouser
Number of shoes (each side) 39
Grouser height 2.1" 53 mm
Shoe width (standard) 20" 510
Ground contact area 3,708 in² 23919 cm²
Ground pressure
(with dozer, ROPS cab)
5.60 psi 0.39 kgf/cm² / 37.8 kPa
Track gauge 5'4" 1620 mm
Length of track on ground 7'8" 2345 mm


  • Alternator, 60 ampere/24V
  • Backup alarm
  • Batteries, 92 Ah/2 x 12V
  • Battery disconnect switch
  • Blade lift cylinders 
  • Color monitor, LCD
  • Decelerator pedal (single pedal)
  • Engine hood
  • Engine intake centrifugal precleaner
  • Engine, swing open side cover
  • Engine shutdown secondary switch
  • Front pull hook
  • Fuel prefilter (10 micron) and fuel filter (2 micron)
  • Grease gun holder
  • High mount foot rests
  • Horn, warning
  • Hydraulic driven radiator cooling fan with reverse clean mode
  • KOMTRAX® Level 4
  • Komatsu Diesel Oxidation Catalyst (KDOC)
  • Locks, filler caps and covers
  • Muffler with curved exhaust pipe
  • Radiator mask, heavy-duty, swing up 
  • Radiator reserve tank
  • ROPS cab**
  • Air conditioner
  • Cab accessories
    --12V power supply (2 ports)
    --Cup holder
    --Rearview mirror
    --Rear view monitoring (1 camera)
    --AM/FM Radio w/remote AUX plug (3.5 mm)
    --70 dBA
  • Work lights
    --3 front, cab mounted
    --2 rear, cab mounted
  • Seat, air suspension, fabric, heated low back, headrest 
  • Seat belt, 76 mm / 3'', retractable
  • Seat belt indicator
  • Sealed electrical connectors
  • Side by side rear mounted cooling package
  • Starting motor, 4.5 kW/24V
  • Steering system, hydrostatic
  • Track roller guards, center and end sections
  • Track shoe assembly
  • Sealed and lubricated
  • 510 mm / 20'' single grouser shoe (EX)
  • 635 mm / 25'' single grouser shoe (PX)
  • Transmission with Variable and Customizable Quickshift
  • Transmission, hydrostatic
  • Underguards, heavy duty
  • Engine
  • Transmission
  • Variable flow turbocharger
  • Water separator

* Dozer assembly and rear mounted equipment are not included in base machine standard equipment
** Cab meets ROPS and FOPS Level 2 standards


  • 700 mm / 27.5'' grouser with AR link
  • Dozer assembly
  • Hitch
  • Hydraulics for rear equipment
  • Track roller guard, full length

Multi-shank ripper:

  • Weight
    470 kg / 1,036 lb
  • Beam length
    1569 mm / 62''
  • Maximum lift above ground
    389 mm / 15''
  • Maximum digging depth
    336 mm / 13''
  • Number of shanks