844 power train components deliver dependable, reliable performance customers expect from Cat wheel dozers
3412E HEUIThe Cat 3412E Hydraulic Electronic Unit Injection engine is rated at 466 kW Net (625 hp) at 2000 rpm.
Injection timingComplete control of injection timing without concern for cam profile limitations.
Complete control of injection duration.Complete control of injection duration. The HEUI system will decrease proportionately with engine speed but can also electronically control the oil supply pressure.
Injection rate shapingInjection rate shaping reduces nitrous oxide (NOx) emissions and reduces engine combustion noise.
Torque ConverterImpeller clutch torque converter allows the operator to modulate rimpull from 100 percent to 20 percent of maximum rimpull.
Axle-shaft, oil-disc brakesAxle-shaft, oil-disc brakes are fully hydraulic, completely sealed and never need adjustment.
Aftercooler Lowers InletAftercooler lowers inlet charge temperature. Reduces thermal stresses that can cause premature wear of pistons, rings and liners.
Injection PressuresHigh injection pressures, independent of engine speed, decrease smoke and emissions while improving response.
PistonsOil-cooled pistons and full-length, water-cooled cylinder liners provide maximum heat transfer for longer component life.
Engine Oil CoolerEngine oil cooler maintains optimum oil temperature for proper cooling and lubrication.
Advanced design and materials provide superior strength.
Structures robotically weldedStructures on the 844 are more than 90 percent robotically welded.
Casting in the engine-end frame.Casting in the engine-end frame are used in critical high-stress areas to help spread the load and reduce the number of parts.
Engine and transmission mounts.Engine and transmission mounts are designed to use mushroom and cup-shaped ISO mounts, reducing component vibration and sound levels.
Box-Section Rear FrameBox-section rear frame absorbs shock loads and torsional forces, solidly maintaining alignment for hitch pins and driveline.
Front FrameFour-plate front frame provides maximum structured strength to resist twisting loads during dozing applications.
Hitch PinsUpper and lower hitch pins pivot on double-tapered roller bearings and are shaped to direct stress away from the end of the weld, resulting in a smoother transition of stress loads.
Spread-Hitch DesignSpread-hitch design helps square up the frame and provides more clearance for hydraulic lines. Double tapered roller bearings and hardened pins resist both horizontal and vertical loads to increase life.
Well-balanced hydraulics deliver precise, low-effort control and trouble-free operation.
Two separate, hydraulic systems.One system is for implements and brakes while the other is for steering and hydraulically-driven engine cooling fan.
Blade ControlArmrest-mounted control lever sends signals to a pilot valve for tilt/tip control and to a main valve for lift/lower control.
Load Sensing Steering.Load sensing steering with STIC Control System is a revolutionary system that integrates steering and transmission into a single controller.
Caterpillar's XT-3 and XT-5 hose.Caterpillar's XI-3 and XT-5 hose, O'ring face seals and large-bore lift and tilt cylinders top off the hydraulic system, delivering the performance and durability owners expect.
Hydrostatic cooling fanHydrostatic cooling fan is used for engine, transmission and hydraulic cooling.
Comfort and control-top operator station will help maximize productivity.
Spacious cab design.Spacious cab design, incorporating innovations for operator comfort and productivity.
Large viewing area.Large, viewing area enhances viewing in all directions.
Blades and Blade Control.
Caterpillar blades are built to handle tough applications. Well-proven Cat components deliver dependable service and ease of operation.
Heavy-duty blade linkage.Heavy-duty blade linkage is common with a Caterpillar D11 Track-Type Tractor.
Blade controlSingle-lever blade control hydraulically operates blade raise, lower, tilt and tip.
Single or dual-tiltOperator has the option of either single or dual-tilt operation by using a switch located on top of control lever.
Caterpillar bladesResilient and durable Caterpillar blades are designed with excellent dozing and rolling characteristics.
Coal BladeCoal blade is designed for precise and productive dozing while helping to retain load control with increased capacity for lighter materials.
Semi-U bladesSemi-U blades combine the characteristics of the S and U blades into one package.
Heavy-duty semi-U bladeThe heavy-duty semi-U blade has the same configuration as the semi-U blade, but it is built with thicker plates for more severe applications.
Less time spent on maintenance means more time on the job.
Easy maintenanceIn addition to the servicing features built into the engine, the 844 includes many other features.
Cat dealers services keep machines operating longer with lower costs.
SelectionMake detailed comparisons of the machines under consideration before buying.
OperationImproving operating techniques can boost one's profits.
MaintenanceMore and more equipment buyers are planning for effective maintenance before buying equipment.
Product SupportNearly all parts are available at the Cat Dealer parts counter.
ReplacementRepair, rebuild or replace?