• 30,821 lbs Operating Weight
  • 131 @ 2200 rpm Horsepower
  • 3.5 yd³ Blade Capacity


The D51EX/PX-24 sets the standard for general-purpose construction dozers. Built for precise, high-speed grading, the new Tier 4 Final engine and electronically-controlled hydrostatic transmission together burn up to 13 percent less fuel and remain easy to maintain. In addition, the new PX model, high capacity, high-wear-resistant, HST dozer blade offers up to 15 percent more production. Also, the Standard Parallel Link Undercarriage System (PLUS) has rotating bushings, which help reduce undercarriage wear especially while traveling in reverse at high speeds. For jobsite applications ranging from golf course construction to highway projects, the Komatsu D51-24 is the obvious choice.

D51EX-24 Walkaround  >


High Capacity High WearResistant HST Dozer Blade

The D51PX PAT high-capacity (4.4 yd3), high wear-resistant blade can increase production.

Production increased by up to 15%

HST with Electronic Control

The D51EX/PX-24 is equipped with Komatsu-designed HST that allows for Quick-Shift or variable speed selection. The HST consists of dual-path closed-circuits, with two variable displacement piston pumps and two variable displacement travel motors. Hydrostatic steering eliminates steering clutches and brakes, providing smooth, powerful turns. Fully electronic control provides complete automatic shifting and enables smooth control. Engine speed is controlled using an electronic fuel control dial.

Komatsu New Emission Regulations compliant Engine

SAA4D107E-3 EPA Tier 4 Final emissions certified engine has a water cooled variable geometry turbocharged and aftercooled 4.5 liter diesel engine which provides up to 13% increased fuel efficiency.

Parallel Link Undercarriage System

Komatsu's PLUS rotating bush design provides less downtime, longer wear, and with up to 40% lower undercarriage maintenance costs, than conventional undercarriage. Rotating bushings eliminate the cost and downtime for bushing turns, and strengthened rollers and links increase wear life up to two times. With PLUS, individual links can be replaced with common track tools.

PAT Dozer with Adjustable Pitch

A high wear-resistant power angle, power tilt dozer blade with adjustable blade pitch is available on the D51EX/PX-24. The hydraulic blade tilt and angling function expands versatility and productivity in a variety of applications.

Swing Up Fan

The D51EX/PX-24 utilizes a swing-up fan with a gas strut-assisted lift system to provide easy access to the (side-by-side) radiator, oil cooler and charge air cooler. The hydraulic fan is reversible to help keep the radiator cores clean and simplify maintenance.

Unrivaled Blade Visibility

The D51EX/PX-24 incorporates Komatsu's superslant nose design. Komatsu's innovative design provides excellent blade visibility for improved machine control and increased efficiency and productivity.



Model Komatsu SAA4D107E-3*
Type 4-cycle, water-cooled, direct injection
Aspiration Variable geometry, water-cooled, turbocharged,
air-to-air aftercooled
Number of cylinders 4
Bore x stroke 107 mm x 124 mm 4.21" x 4.88"
Piston displacement 4.5 ltr 275 in³
Governor All-speed, electronic
SAE J1995 - Gross 99 kW 133 HP
ISO 9249 / SAE J1349 - Net 98 kW 131 HP
Hydraulic fan at maximum speed - Net 91 kW 122 HP
Rated rpm
2200 rpm
Fan drive type Hydraulic
Lubrication system:
Method Gear pump, force lubrication
Filter Full-flow

*EPA Tier 4 Final 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 damage by debris. Bolt-on sprocket ring with triple labyrinth seal design.

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
97 ltr/min 26 U.S. gal/min at rated engine rpm.
Relief valve setting 27.4 MPa / 280 kg/cm² 3,983 psi
Hydraulic cylinders Double-acting, piston type
Number of cylinders: Bore Bore
Blade lift / 2 90 mm 3.5"
Blade tilt / 1 100 mm 4"
Blade angle / 2 90 mm 3.5"
Hydraulic oil capacity (refill):
Power angle tilt dozer 64 ltr 17 U.S. gal
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 9.0 km/h 5.6 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)
Forward Reverse
1st 0–3.4 km/h
0–2.1 mph
0–4.1 km/h
0–2.5 mph
2nd 0–5.6 km/h
0–3.5 mph
0–6.5 km/h
0–4.0 mph
3rd 0–9.0 km/h
0–5.6 mph
0–9.0 km/h
0–5.6 mph
Travel speed
(variable mode)
0–9.0 km/h
0–5.6 mph
0–9.0 km/h
0–5.6 mph

Operating Weight

Tractor weight: Including ROPS cab, U frame for Power Angle Tilt (PAT)
dozer, rated capacity of lubricant, coolant, full fuel tank,
operator, and standard equipment.
12330 kg
27,182 lb
Operating weight: Including Power Angle Tilt (PAT) dozer, ROPS cab, operator,
standard equipment, rated capacity of lubricant, hydraulic
control unit, coolant, and full fuel tank.
13980 kg
30,821 lb

Service Refill Capacities

Coolant 37 ltr 9.8 U.S. gal
Fuel tank 270 ltr 71.3 U.S. gal
Engine oil 16ltr 4.2 U.S. gal
Hydraulic tank 64 ltr 17 U.S. gal
Final drive (each side) 5.5ltr 1.5 U.S. gal
Diesel Exhaust Fluid (DEF) tank 20.5 ltr 5.42 U.S. gal


Palm Command Control System (PCCS) joystick control for all directional movements. Pushing the joystick forward results in forward machine travel, while pulling it back 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: 2.4 m 94"

*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 & lubricated track Track tension easily adjusted w/grease gun
Number of track rollers (each side) 7
Type of shoes (standard) Single grouser
Number of shoes (each side) 44
Grouser height 55 mm 2.2"
Shoe width (standard) 560 mm 22"
Ground contact area 30750 cm² 4,766 in²
Ground pressure
(with dozer, ROPS cab)
0.40 kgf/cm² / 39.9 kPa 5.79 psi
Track gauge 1790 mm 5'10"
Length of track on ground
2745 mm 9'0"


  • Accumulator for Electric Proportional Control (EPC)
  • Air cleaner, dry, double element type with caution lamp on monitor
  • Air conditioner (A/C)
  • Air inlet
  • Alternator, 24 V/85 A
  • Back-up alarm
  • Batteries, large capacity 24 V/92 Ah
  • Cab accessories
    — 12 V × 2 power supply
    — Cup holder
    — Rear view mirror
    — Rear view monitor system
    — Bluetooth/USB compatible radio with remote AUX plug (3.5 mm)
  • Crankcase guard and underguard
  • Decelerator/brake pedal (Single pedal)
  • Electronically controlled Hydrostatic Transmission (HST) with quick-shift and variable speed settings
  • Electronic monitor panel with on-board diagnostics
  • Engine hood and side panels
  • Engine, KOMATSU SAA4D107E-3, gross output of 98 kW 131 HP, direct injection, water-cooled turbocharged, air-to-air aftercooler, cooled EGR, EPA Tier 4 Final and EU Stage 4 emissions certified
  • Fan, hydraulic driven, electronic control
  • Filler cap locks and cover locks
  • Fluid sampling ports
  • Foot rest, high mounted
  • Fuel pre-filter (10 micron) and fuel filter (2 micron)
  • Grease gun holder
  • High altitude arrangement (No fuel adjustment up to 2300 m)
  • Horn
  • Hydraulics for PAT dozer
  • Intake pipe with precleaner
  • Komatsu Diesel Oxidation Catalyst (KDOC)
  • KOMTRAX Level 5.0
  • Large high-resolution LCD
  • LED worklights
  • Lunch box holder
  • Marks and plates, English
  • Operator Identification System
  • Palm Command Control System (PCCS) with electronic control for travel control
  • Palm Command Control System (PCCS) with EPC for blade control
  • Power turn with counter rotation
  • Pullhook, front
  • Radiator guard grid
  • Radiator reserve tank
  • Real-time DEF monitoring
  • Rear-hinged radiator guard
  • Reverse travel speed presets
  • ROPS cab
    Meets ISO 3471, SAE J/ISO 3471 ROPS standards, and ISO 3449 FOPS standard.
  • Seat belt, 76 mm 3" retractable
  • Seat, air suspension, fabric, heated, low back, headrest
  • Shovel holder
  • Starting motor, 24 V/4.5 kW
  • Selective Catalytic Reduction (SCR)
  • Self adjusting roller
  • Sprockets, bolt-on
  • Sprocket inner guard
  • Track roller guards, end section
  • Track shoe assembly (PLUS)
    — Sealed and lubricated
    D51EX-24: 560 mm 22" single grouser shoe
    D51PX-24: 710 mm 28" single grouser shoe
  • Triple labyrinth final drive
  • Water separator


  • Dozer assembly
  • Hitch
  • Hydraulics for rear equipment
  • Track roller guard, full length

Multi-shank ripper:

  • Weight: 860 kg 1,874 lb
  • Beam length: 1556 mm 5'1"
  • Maximum lift above ground: 380 mm 1'3"
  • Maximum digging depth: 425 mm 1'8"
  • Number of shanks: 3