COMPLETING the Cat D-Series Track Loader lineup is the new 973D, featuring load-sensing hydraulics, joystick steering, new operator's station (with tilting cab) and 10 per cent more power than its 973C predecessor. The new loader carries on the 973C's "all-purpose performer" reputation and retains much of its design, including the Cat C9 engine, hydrostatic drive, single-fabrication mainframe, Z-bar loader linkage and oscillating undercarriage. The 973D is a "one-machine workforce" with the features to take on jobs at construction sites or in the harsh environments of steel mills, landfills, quarries and demolition sites.

The 973D's new closed-centre, load-sensing implement hydraulic system uses a variable-displacement pump that produces only the precise volume of oil actually required for the job at hand. By contrast, the 973C's hydraulic pump produced a constant oil volume, whether required or not. The net result is that the 973D pumps less oil, thus conserving fuel, generating less heat and freeing horsepower to drive the tracks more efficiently. The new system also allows seamless, simultaneous use of lift, tilt and travel functions.

Complementing the new hydraulic system are lift and tilt cylinders using position-sensing electronics, which allow operators to set lift and tilt kick-outs from the cab. Kick-outs are quickly reset for each job – or even each truck – to assure fast cycle times. In addition, end-of-travel snubbing assures that cylinders stop smoothly with less shock.

In the new operator's station, buyers now can choose either joystick steering or pedal steering. The steering joystick also provides transmission control, allowing the operator to effortlessly select travel direction and ground speed, while the pedal-steer system works in conjunction with the Cat "V-pattern" transmission controller. Both systems assure fast, precise steering — but now buyers can select the system preferred by their operators.

Buyers also have a choice of loader controls – either joystick or two-lever. The 973C offered this choice, but loader controls for the new 973D are seat-mounted and electro-hydraulically actuated, compared with console-mounted and pilot-actuated (hydraulically assisted). The new seat-mounted, low-effort controls move with the operator as the seat is adjusted, transmit less vibration and provide extremely fast, precise hydraulic response.

The new cab is sound-suppressed (rated at 74 dB-A), sealed, pressurised, air-conditioned, resiliently mounted and tilts (30 degrees in the field, 90 degrees in the shop) for access to major components. Increased glass area improves visibility all around, and the new fender design yields sharper sightlines out the rear window. A compact new dash includes both a gauge cluster that monitors vital systems and the Messenger display screen, which provides real-time performance and diagnostic information.

The 8.8-liter, 196 kW Cat C9 diesel engine, which meets US EPA Tier-3 and European Union Stage IIIA standards, uses proprietary Caterpillar Acert Technology for emissions-control and fuel-economy. A new on-demand, viscous-clutch cooling fan helps further lower fuel consumption and sound.

The electronically controlled Cat Hystat hydrostatic drive system powers and controls each track independently via a variable-displacement pump and motor. The Hystat system allows both tracks to be powered through gradual turns, simplifies straight-line travel when working across slopes and provides exceptional manoeuvrability with its counter-rotation capability.