• 27,381 lbs Operating Weight
  • 130 @ 2200 rpm Horsepower
  • 3.5 - 3.8 yd¬≥ Blade Capacity


Introducing the Next Generation of Machine Control

Intelligent Machine Control machines have the following advantages over dozers with external grade control systems.

  • Innovative
    Automated operation from rough dozing to finish grade.
  • Intelligent
    New dozing mode, load control performance features.
  • Integrated
    Standard factory installed integrated system.
  • No Cables
    No coiled cables between machine and blade.
  • No Climbing
    GNSS antenna and mast removed from blade.
  • No Connections
    No daily connections required between machine and blade.


Automated Blade Control, from Rough Dozing to Finish Grade. Straight to Grade.

  1. Blade moves to target surface until load reaches a preset level.
  2. The blade automatically raises to minimize track slip.
  3. Should the load decrease, blade will lower to re-load blade to an optimum level.


Cab Top GNSS Antenna

No blade mounted GNSS antenna(s), cables to worry about damaging with cab top GNSS antenna. Reduced risk of theft due to low visibility as viewed from ground level.

Closed-center Load Sensing Sytem CLSS Hydraulic System

With CLSS hydraulics, blade lever stroke is directly proportional to blade speed, regardless of the load and travel speed. This results in superb fine controllability.

Electronic Controlled Hydraulic System EPC Blade Control Joystick

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

HST with Electronic Control

The D51 is equipped with a Komatsu-designed Hydrostatic Transmission (HST) that allows 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 full automatic shifting and enables smooth control. Engine speed is controlled using an electronic fuel control dial.

Hydraulically-driven Swing-up Fan

The D51i-22 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 has a “cleaning” mode. The fan rotates in the reverse direction and helps to clear off objects in front of the cooling areas. The fan is protected by thick steel louvers and an additional fan screen for added durability.

Hydrostatic Transmission (HST) Control System

The HST controller monitors engine output and work equipment/travel load. It controls HST pump and motor displacement to provide the optimum speed and drawbar pull. Power to both tracks during turns and counter-rotation makes the D51 extremely maneuverable.

Stroke Sensing Hydraulic Cylinders

Robust stroke sensing hydraulic cylinders employ proven Komatsu sensor technologies for accurate finish grade performance. Stroke sensing angle cylinder allows machine control system to know the angle of the blade.



Model    Komatsu SAA6D107E-1* 
Type    4-cycle, water-cooled, direct injection 
Aspiration    Turbocharged, air-to-air aftercooled 
Number of cylinders   
Bore x stroke  4.21" x 4.88"  107 mm x 124 mm 
Piston displacement  408 in³  6.69 ltr 
Governor    All-speed, electronic 
SAE J1995 - Gross  133 HP  99 kW 
ISO 9249 / SAE J1349 - Net  130 HP  97 kW 
Hydraulic fan at maximum speed - Net  120 HP  90 kW 
Rated rpm
  2200 rpm
Fan drive type    Hydraulic (reversible) 
Lubrication system:     
Method    Gear pump, force lubrication 
Filter    Full-flow 

*EPA Tier 3 emissions certified

Final Drive

Two-stage planetary gear integrated into axial piston travel motors. Compact in-shoe mount reduces risk of damage by debris. Bolt-on sprocket segments for easy replacement.

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 26.2 U.S. gal/min at rated engine rpm.     
Relief valve setting  3,983 psi  27.4 MPa / 280 kg/cm² 
Hydraulic cylinders    Double-acting, piston type 
Number of cylinders:  Bore  Bore 
Blade lift / 2  3.54"  90 mm 
Blade tilt / 1  3.94"  100 mm 
Blade angle / 2  3.54"  90 mm 
Hydraulic oil capacity (refilling):     
Power angle tilt dozer  16.6 U.S. gal  63 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 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  0–2.1 mph
0–3.4 km/h 
0–2.5 mph
0–4.1 km/h 
2nd  0–3.5 mph
0–5.6 km/h 
0–4.0 mph
0–6.5 km/h 
3rd  0–5.6 mph
0–9.0 km/h 
0–5.6 mph
0–9.0 km/h 
Travel speed
(variable mode) 
Forward  Reverse 
  0–5.6 mph
0–9.0 km/h 
0–5.6 mph
0–9.0 km/h 

Operating Weight

Tractor weight:    Including ROPS cab, rated capacity of lubricant, coolant, full fuel tank, operator, and standard equipment. 
D51EX-22  24,074 lb  10920 kg 
Operating weight:    Including power angle tilt dozer, ROPS cab, operator, standard equipment, rated capacity of lubricant, coolant, and full fuel tank. 
D51EX-22  27,381 lb  12420 kg 

Service Refill Capacities

Coolant  9.3 U.S. gal  35 ltr 
Fuel tank  71.3 U.S. gal  270 ltr 
Engine oil  5.3 U.S. gal  20 ltr 
Hydraulic tank  16.6 U.S. gal  63 ltr 
Final drive (each side)  1.1 U.S. gal  4.0 ltr 


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) eliminates steering clutches and brakes, providing smooth powerful turns. Fully electronic control enables smooth control. The PCCS utilizes shift buttons to increase and decrease speed.

Minimum turning radius:  7'10"  2.39 m 

As measured by track marks on the ground at pivot turn.


Suspension    Oscillating equalizer bar and pivot shaft 
Track roller frame    Monocoque, large section, durable construction 
Rollers and idlers    Lubricated track rollers 
Lubricated tracks:    Unique seals help prevent entry of foreign abrasive material into pin to bushing clearances for long service life. 
Parallel Link Undercarriage System (PLUS)    Increased component size and strength, and rotating bushing design provide extended wear life and lower maintenance. 
Number of track rollers (each side)    7
Type of shoes (standard)    Single grouser PLUS 
Number of shoes (each side)    44 
Grouser height  2.2"  56 mm 
Shoe width (standard)  22"  560 mm 
Ground contact area  4,752 in²  30643 cm² 
Ground pressure
(with dozer, ROPS cab) 
5.76 psi  0.41 kgf/cm² / 39.7 kPa 
Track gauge  5'10"  1790 mm 
Length of track on ground
9'0"  2736 mm 


  • Air cleaner, dry, double element type with caution lamp on monitor 
  • Decelerator pedal 
  • Fan, hydraulic driven, electronic control, reversible
  • Water separator 
  • Alternator, 60 amp (24 V) 
  • Back-up alarm 
  • Batteries, large capacity 1000 CCA,170Ah
  • Starting motor, 5.5 kW 
  • Brake pedal 
  • Electronically controlled Hydrostatic Transmission (HST) with Quick-shift and variable speed settings
  • Track roller guards, center and end section 
  • Track shoe assembly w/sealed and lubricated link assembly
    – D51PXi-22: 710 mm / 28" HD single grouser shoes PLUS 
  • Crankcase guard and underguard 
  • Sprocket inner guard 
  • 12 amp (12V) power port (cab only) 
  • Seat, high back, cloth, suspension type
  • Cigarette lighter (24 V, cab only) 
  • Cup holder 
  • Electronic monitor panel with on-board diagnostics 
  • Foot rests, high mounted 
  • Horn 
  • AM/FM radio 
  • Rearview mirror 
  • Power Angle Tilt dozer assembly, inside arms (3350 mm / 11' blade) 
  • Intelligent Machine Control
  • Filler cap locks and cover locks 
  • KOMTRAX function Level 2+ 
  • Lighting package - (3 front, 2 rear cab)
  • Pullhook, front


  • Drawbar, long type 
  • Track roller guard, full length 
  • Hitch 
  • Guarding 
  • Multi-shank ripper (for D51EXi/PXi)