The unique Komatsu HYDROSHIFT transmission with planetary gears is hydraulically-controlled and force-lubricated. Efficient power flow and simplified direction and speed changes (2 forward and 2 reverse).
Single steering lever controls all direction movement. Dry, multipledisc steering clutches are PPC controlled and interconnected with dry, contracting-band, steering brkes to allow easy, light-touch
steering/braking actions. A PPC valve built into the steering circuit facilitates smooth shockless steering control. Inching pedal assures smooth, easy starting and stopping, precise inching approaches to obstacles and impact digging.
Spur gear, single-reduction final drives.
Operating weight includes; power angle tilt dozer, rated capacity of lubricant, coolant, full fuel tank, standard equipment and operator 8,710 lb 3950 kg.
A single joystick on the left controls all speed and directional changes including:
• 1st to 2nd
• Forward and reverse
• Right and left steering
A single joystick on the right controls all blade functions including:
This left and right joystick system offers unparalleled control for shorter cycle times.
Easy-to-see instrument panel
Ergonomically arranged meters and lamps make it easier to check the machine condition. In addition, fuel meter and dust indicator lamp installed on the panel for easy servicing.
Walk-through operator's compartment
The operator's compartment has a complete walk-through design, making for easy getting on and off.
KOMTRAX equipped machines can send location, SMR and operation maps to a secure website utilizing wireless technology. Machines also relay error codes, cautions, maintenance items, fuel levels, and much more.
Efficient HYDROSHIFT transmission
The D21-8 is equipped with Komatsu's unique HYDROSHIFT transmission, assuring
smooth gear shifts, powerful traction and low fuel consumption.
It consists of a damper and planetary gear packs. The HYDROSHIFT transmission makes two previously incompatible factors compatible: It efficiently converts engine power to traction with minimal power loss through a damper and it offers smooth, easy shifting
through a powershift transmission.
Unlike ordinary powershift transmissions with torque converters, traction does not decrease, even when the engine is running at partial throttle.
The long track and well-positioned center of gravity give good machine balance and make grading operations and operations on slopes easy. In addition, the machine can travel over soft ground easily, and it can escape from muddy areas without problem.
Spin-on type filters are used throughout the machine, making it easy to replace filter elements. Air cleaner with automatic evacuator extends cleaning interval of the air cleaner.
Automatic de-airation system with electric feed pump
Ejects air in the fuel system, simply turning on the ignition key when restarting the engine.
Single-lever steering/speed/ directional change
All the directional changes are carried out with single lever, ensuring smooth turn and superior productivity.
Fuel-efficient 4D94LE-2 engine
The Komatsu 4D94LE-2 features a direct-injection fuel system. Intake air is swirled into the combustion chamber where it is mixed with injected, atomized fuel, providing optimum combustion. This fuel system not only contributes to greater power and fuel savings, but also ensures reduced noise and cleaner exhaust. A cushion mounted engine reduces noise and vibration.
Lifetime lubricated idlers, track rollers and links
Alternator, 12 V, 40 A
Batteries, 12 V, 64 Ah (5 hrs rate capacity)
Dry-type air cleaner with automatic dust evacuator and
dust indicator lamp
Dry-type, interconnected steering clutches and brakes
Electric starting motor, 12 V, 2.3 kW
End track guiding guards
Hydraulic track adjusters
(including 2 front and 1 rear lights)
Lubricated track links
Power angle tilt dozer, inside arms
ROPS/FOPS Level 2 canopy*
Seat belt, 76 mm 3"
Shoes, 300 mm 11.8" single-grouser(D21A-8)
Single-lever control for blade
Transmission, F2- R2
Vandalism protection locks and filler cap locks
5-roller track frames
*ROPS canopy meets all OSHA/MSHA standards and
*Rops cab or Rops canopy must be ordered for all
3-point hitch with swing drawbar
Air conditioner for cab
Hydraulics for three point hitch
Perforated radiator mask
Track-roller guards, full length
D21A-8 Optional Shoes
11.8' 300mm triple-grouser shoe with hole
*Additional weight: +44 lb +20 kg
Ground contact area: 1,570 in² 10110cm²
*Additional ground pressue (tractor): +0.03 PSI +0.2 kPa +0.002 kg/cm²
11.8' 300mm rubber shoe
*Additional weight: -165 lb -75 kg
Ground contact area: 1,570 in² 10110cm²
*Additional ground pressue (tractor): -0.1 PSI -0.7 kPa -0.007 kg/cm²
13.4' 340mm single-grouser shoe
*Additional weight: +30 lb +66 kg
Ground contact area: 1,780 in² 11460cm²
*Additional ground pressue (tractor): -0.57 PSI -3.9 kPa -0.04 kg/cm²
*Including Dozer equipment
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