The D39 frame is designed using advanced computer - aided engineering. The frame structure combines the main frame and track frame with connecting bars to deliver the ideal stiffness required in a small size dozer. Travel motors and final drives are mounted inside the track shoe for protection from rocks and stumps and for improving durability. The life of undercarriage and reliability are greatly extended by the use of large size links, pins, bushings, and unique dust seals.

D39 Dozer uses HST dynamic brakes to ensure safe operation. The newly developed 3-axis PPC valve and ergonomically designed joystick provide light operating effort and excellent blade response. PCCS (Palm Command Control System) joystick controls all directional movements. Hydrostatic steering eliminates steering clutches and brakes, providing smooth powerful turns.
The large ground contact area created by the long tracks and wide track gauges, combine with a low centre of gravity to make D39EX-21 a stable and well balanced machine that can perform precise grading work on rough as well as inclined terrain. The slim engine hood and well located operator seat provide excellent visibility to the blade. This clear blade visibility increases grading efficiency and reduces operator guesswork.
With the hydraulic closed - centre load sensing system, the blade lever stroke is directly proportional with blade speed, regardless of the load and travel speed. The benefits include precise and responsive operation due to the pressure compensation valve and reduced fuel consumption by discharging only the required amount of oil from the pump.
An electronic monitoring system prevents minor problems from developing into major ones. All meters and gauges are controlled by a microcomputer, which provides a wide indication range for an easier, more precise reading.
Thanks to its host of advanced features and productivity edge, the D39EX-21 Dozer has become a hit in the Indian construction industry in a short time and is here for many years to come.