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Komatsu D21A-8 Crawler Dozer Has Improved Power, Reliability

Fri June 04, 2010 - National Edition
Construction Equipment Guide

Komatsu America Corp.'s D21A-8 crawler dozer, designed primarily for slope work and fine grading applications, features HYDROSHIFT drive transmission and a powerful, fuel-efficient Komatsu 4D94LE-2 engine for advanced grading control, ease of operation and increased power and maneuverability.

The D21A-8 operates with 40 hp (30 kW) at 2,450 rpm and features an operating weight of 8,688 lb. (3,941 kg) and blade capacity of .75 cu. yd. (.6 cu m) (SAE). The machine's lightweight, compact design allows contractors to use the same trailer used for skid steers while still remaining below weight limits that would require drivers to obtain a CDL.

For increased balance and maneuverability on sloped, muddy and other adverse ground conditions, the D21A-8 is equipped with a long track and well-positioned center of gravity. The added options of either a rubber or steel track chain allow the unit to travel easily over soft ground and mud.

Powerful, Smooth Transmission

The power of the D21A-8 is delivered through a direct drive power train utilizing Komatsu's HYDROSHIFT transmission for smooth gearshifts, powerful traction and low fuel consumption. The HYDROSHIFT transmission efficiently converts engine power to traction with minimal power loss, making for more efficient operation in steady-load applications.

Joystick Controls for Simplified Operation

These upgraded features include a single, left side pressure proportional control (PPC) joystick control for direction and gear changes. The left hand joystick controls all directional and speed changes. When steering, the PPC valve that is built into the steering circuit facilitates smooth, shockless steering, allowing light-touch steering/braking action. The single, mechanical blade control lever located at the operator's right hand operates the blade lift, tilt, dig and angle functions.

Adding to the ease of operation and precise control is the transmission inching pedal. When combined with the joystick controls, this provides more precise grading accuracy while an optional decelerator pedal provides the operator infinite speed control. The HYDROSHIFT transmission allows for easy travel speed changes with the simple twist of a control lever, allowing the operator to tailor speed to the given application.

Minimal Environmental Intrusion With Rubber Track Option

The optional rubber track gives contractors a machine with less traveling noise and less vibration transmitted to the ground, and the ability to move the machine over asphalt and concrete without taking extra steps to protect the surface. The smooth, quiet design makes this machine ideal for work in urban areas. Track reliability is ensured through double-layer bias steel cords and main steel cords, with a unique hard rubber that is overlaid on the steel base in a lug-type pattern.

Improved Maintenance

Knowing that maintenance is critical for successful equipment upkeep and keeping operating costs down, Komatsu offers several features with the D21A-8 for simplified maintenance. A conveniently located instrument panel makes it easy to check the machine's vital information and the fuel meter and dust indicator lamp are located directly in front of the operator for easy monitoring. Other items aiding in maintenance and machine durability include:

  • Spin-on filters throughout the machine enable easy replacement.
  • Lifetime lubricated idlers and track rollers eliminate periodical greasing and minimize pin and bushing wear.
  • Optional lubricated track links reduce power loss that results from pin and bushing friction while improving operator comfort.
  • Roll over protection structure (ROPS) canopy is offered as a standard safety measure.

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