The Cat® C6.6 is a 6.6 liter (403 in3) displacement, six-cylinder, in-line configured engine that utilizes the Caterpillar Common Rail fuel system for fuel delivery. It uses ACERT™ Technology, a series of Caterpillar engineered innovations that provide advanced electronic control, precision fuel delivery and refined air management, resulting in outstanding performance and lower emissions. The C6.6 with ACERT Technology offers a compact design with big, heavy-duty engine features for outstanding durability, reliability and performance. The C6.6 incorporates a new cross flow cylinder head design, 4 valve head and an ADEM™ A4 electronic controller. The C6.6 also features proven cylinder block, pistons and crankshaft and incorporates the common rail fuel system. ACERT™ technology enables the C6.6 engine to meet the U.S. EPA Tier 3, European Union Stage IIIA and Japan Ministry of Land, Infrastructure & Transport Step 3 emissions standards, which dramatically reduce nitrogen oxide (NOx) and other emissions. ACERT™ technology used on the C6.6 consists of three basic building block systems: electronic control, fuel delivery, and air management. These have been refined to control the combustion process to a higher degree than ever before possible.

The Advanced Diesel Engine Management — Electronic Control Module continuously monitors important engine conditions and functions. It uses sensors throughout the engine to regulate fuel delivery and all other engine systems that require input to manage load and performance. ADEM™ A4 is the brain behind engine responsiveness, self-diagnosis, controlling emissions, and fuel economy.

Through multiple injection fuel delivery, fuel is introduced in the combustion chamber in a number of precisely controlled microburst. Injecting fuel in this way allows for precise shaping of the combustion cycle. The ADEM™ A4 module directs the injectors to deliver precise quantities of fuel at exactly the right times during combustion cycle. This process provides precise control over a range of combustion variables, which can be regulated to produce higher performance with fewer emissions. Fuel is delivered at high pressure to each combustion chamber through a Caterpillar designed injector linked to a high pressure Common Rail.

Air management is a key concept in optimizing engine performance and controlling emissions. Engines must breathe clean cool air in order to perform. To aid this, the C6.6 uses a turbocharger fitted with a smart waste gate to give precise and reliable control of the boost pressure. A new cross-flow design in the cylinder head facilitates air movement, while tighter tolerances between the piston and cylinder liner are reducing blow by gases.

The C6.6 uses an oil-lubricated high-pressure fuel pump to feed the common rail. By using an oil-lubricated fuel pump, the C6.6 has been designed to be more tolerant of alternative fuels.

An electrical fuel-priming pump, standard, is located between the fuel tank and the combined water separator/primary fuel filter.

The Electronic Speed Selector Switch (A), a “rocker” switch located on the right console, sets the engine rpm. The ADEM A4 engine controller will always start the engine in low idle. The engine rpm can be seen on the digital display of the instrument cluster in the gage cluster or in the performance menu in Messenger.

The air-to-air after cooler is a single pass, aluminum, heat exchanger or cooling system for the pressurized air coming from the turbocharger, before it enters the engine intake manifold. Cooling the pressurized air from the turbocharger makes the engine intake air even denser. The increased air volume in the cylinders results in more power, improved combustion, and reduced exhaust emissions.

Unit injectors and high pressure fuel lines can be serviced individually, without the need to service the whole fuel system.

The engine is installed using rubber mounts to reduce the transfer of engine vibration to the frame and cab, lowering operator vibration, sound levels, and fatigue.

Rear engine location allows excellent forward visibility, while serving as a working counterweight. It also helps reduce radiator plugging while providing easy service access to the engine and other major components.

The cooling system is a single cooling unit, which includes Radiator, ATAAC, Oil cooler and Fan installation. The cooling module is located at the rear of the loader, away from dust and debris stirred up by the bucket while the machine is working.

The fan is a hydraulic demand type one with optional reversible function, operating in sucker mode. It gives the best efficiency and avoids also sucking the dust and debris coming from the outside into the cooling package. The complete cooling package has been designed for a very easy maintenance with a complete accessibility to the cores for cleaning (fan door swing out opening, latches), and a very high safety level.

Air conditioning is standard on 953D. Both the air conditioning and the heater deliver filtered, pressurized, temperature-controlled air to the operator and windows through 10 louvered vents.

The Caterpillar air-suspension seat, with side-to-side isolator, is ergonomically designed and fully adjustable for maximum operator comfort and control. Retractable seat belt is 75 mm (3 in) wide for positive, comfortable restraint.

Seat mounted controls provide less vibration for the operator and a combined seat and controls adjustment.

The right hand side console features an adjustable armrest, wrist rest and joystick mount. The left armrest height is adjustable. Total adjustability lets the operator customize the armrests to the most comfortable position.

Messenger is a new electronic monitoring system with real-time, visual feedback on engine and machine operating conditions. It provides information on diagnostic data, maintenance, and allows operating settings such as implement reactions.

The system controls allow quick speed and directional changes from a single control lever for maximum maneuverability. Steering pedals can be adjusted from 35° to 50° depending on operator preference and allow precise control of each track independently and on-demand counter rotation. The brake pedal supplements dynamic hydraulic braking provided by the hydrostatic drive system.

The speed mode switch allows the operator to choose between “work mode” and “travel mode” to best match the machine speed to various job conditions. Switching between travel and work mode takes effect immediately.

The new electro hydraulic implement controls on the 953D provide the operator with responsive, smooth and precise control of bucket and lift arms. Choice of joystick or two-lever control is available for bucket lift and dump.

Automatic kickouts are part of the electro-hydraulic controls; adjust from inside the cab with a simple rocker switch. Kickout stops are hydraulically cushioned for greater operator comfort and less material spillage.

Large windows use tinted glass to reduce glare and provide an excellent view to the bucket, tracks, and around the engine enclosure to the rear.

The rearview mirror is located above the front windshield, maximizing the operator’s visibility.

A dome light is located in the cab headliner.

A standard feature in the cab is a Radio Installation, which includes a 24-volt to 12-volt converter and speakers. A Caterpillar heavy-duty (AM/FM) radio/CD player and satellite radios are available from dealers.

Storage spaces include a removable lunch box, a beverage holder and storage and a coat holder.

Up to eight working lights are available on the 953D.

The door’s release lever is accessible from the ground and the seat to unlock the door conveniently.

Eliminate machine theft and unauthorized usage with the Cat Machine Security System (MSS). It is integrated into the machine’s electronic system and can protect your equipment by requiring a uniquely coded key to start the machine.

The gauge cluster provides all necessary information within the operator's normal line of sight. The 953D gauge cluster display includes:

• Four direct reading gauges
• Fifteen alert indicators
• A numeric message display

The fifteen alert indicators used on the 953D are: 1. Reversible fan 2. Water separator 3. Fuel filters plugging 4. Fuel level 5. Engine air filter plugging 6. Machine security system 7. Ether starting aid 8. Warning lamp 9. Parking brake 10. Operator presence 11. Hydraulic lockout 12. Hydraulic oil filter 13. Bucket float 14. Lift kickout/lower kickout 15. Bucket leveler

The gauge cluster self-test verifies that the main display module is operating properly every time the key start switch is turned from the “off” to the “on” position. NOTE - If the machine is not equipped with Messenger, the numeric display will show fault codes.

The electronically controlled hydrostatic drive system automatically matches machine travel speed to the combined travel and implement loads on the machine, enabling maximum travel speed, up to the speed selected by the operator.

Hydrostatic system has integrated electro-hydraulic controls, sized for optimum performance and efficiency. Position in the machine provides ease of access for serviceability.

Variable displacement pumps and drive motors are electronically controlled by the EHC, offering high efficiency and precise travel. Each track is independently driven by a separate hydraulic circuit consisting of one pump, connected by Cat XT-6™ hydraulic hose and couplings to a piston motor.

Travel speeds are infinitely variable between zero and top speed. Two speed modes “work” and “travel”, provide two different speed ranges to best match machine speed and torque to the job conditions for maximum productivity. Maximum travel speed is 10 kph (6.2 mph) when the switch is set in the travel position.

The operator controls the speed of the machine and the direction of travel with a single “Speed-Direction control Lever” (SDL) located on the left console. The “reverse V” pattern of the SDL is designed to prevent an accidental full-speed-forward command when the loader encounters sudden resistance while traveling forward.

Braking is accomplished by moving the Speed-Direction control lever on the left console to a slower position (closer to the top of the “Reverse V”), or all the way to the “Brakes-on” position (at the point of the “Reverse V”), The center foot pedal can also be used for emergency braking.

Steering is accomplished by changing relative pump flows and/or motor displacements, which causes one track to rotate slower than the other track. A more aggressive steering command (pushing one foot pedal down farther) will cause one track to stop/reverse while the other track continues to rotate.

The hydrostatic drive train also offers independent power and control of each track, with fast acceleration, infinitely variable speeds, and automatic, on-the-go, direction changes for each track. The operator can command smooth “power turns” or even counter-rotation of the tracks by simply pushing one of the steering pedals. The Caterpillar hydrostatic drive system manages itself, freeing the operator to concentrate on using the Cat track loader’s superb agility, speed, and maneuverability to do more productive work.

Electro hydraulic implement controls on the 953D provide the operator with responsive, smooth and precise control of bucket and lift arms. They also allow the operator to set personal parameters through the optionl Messenger such as implement reactions.

The standard programmable automatic kickouts provide flexibility and productivity for precise load and dump target heights. Tilt and lift kickouts are set by positioning the bucket or work tool and setting a rocker switch in the cab.

The 953D features a load sensing hydraulic system that automatically adjusts to operating conditions to provide only the hydraulic flow required by the implement for improved fuel efficiency.

Position sensing cylinders allows to:

• Set lift and tilt kickouts at any positions according to the applications without operator leaving the cab
• Advanced automatic features as drop catch (accelerate and stop smoothly) & snubbing (smooths start and stop cylinder motion)
• Set tilt and lift kickouts
• Sensing of the cylinder end of stroke
• Prevent unintended motion.

SystemOne™ is the latest innovation in a century of undercarriage leadership. Nearly every major undercarriage improvement over the last 100 years has come from Caterpillar. It was designed to reduce customers’ operating costs and maintenance intervals. The revolutionary Cat SystemOneTM Undercarriage provides maximum undercarriage life and reliability no matter the application, environment or underfoot conditions. Built to last longer and require less maintenance it ensures a dramatic drop in operating costs.

The track roller frames are a welded, box section design, which provides strength and resistance to bending without adding extra weight. The track roller frames are pinned at the rear to the loader main frame with pivot shafts, which allow the front of the track roller frames to swing or oscillate about the pivot shafts at the rear.

Better, more rigid guiding. The guiding system contacts link rails instead of pin ends and helps keep the track within the roller system.

The 953D has six track rollers, which spread machine weight over a large area and a single upper carrier roller on each side mounts to the machine mainframe. The rollers and carrier rollers have been redesigned to run with the system. This will lead directly to better guiding. All rollers in this new system are all single flange rollers with increased flange diameter. This will also increase your guiding capability.

Factory-sealed cartridge joints are welded to control end play. They offer improved seal integrity through an innovative new sealing system and do not depend on the link interface to remain sealed. As with all new Cat undercarriage products, they are filled with special oils.

The shoes for SystemOne™ are unique to this system. Several track shoe types tailor your machine for work in all underfoot conditions. The SystemOne links have a straight rather than offset bolt hole pattern. Double grouser standard or narrow track shoes are available. The standard shoe can be fitted with center hole to reduce material packing.

The sprockets, thanks to the rotating bushing design track, will be able to be reused over the life of a couple of undercarriages. This helps to cut down on replacement cost.

The undercarriage on the 953D features an “oscillating track roller frame design” which decreases ground shock to the machine, increases machine stability, and provides a smoother, more comfortable ride for the operator. Oscillating track roller frames keep more of the track on the ground when operating on uneven terrain, which increases machine stability, felt by the operator, allowing faster machine operation, increased machine productivity and reduced operator fatigue.

The track adjuster and mechanical recoil system uses a large recoil spring and grease filled adjustment cylinder, which allows the idler to move forward and back to maintain proper track tension as it absorbs undercarriage shock loads.

The equalizer bar is pinned in its center to the machine mainframe and at the ends to each track roller frame. This allows the forward ends of the track roller frames to oscillate, or move vertically, to keep more track on the ground in uneven underfoot conditions. The equalizer bar also provides a more stable work platform for the operator, who will be comfortable working at faster speeds for increased productivity.

The 953D Main Frame and Loader Tower is a single, slab rails with reinforced crossings, with castings and forgings incorporated at points of high stress, to distribute those stresses over wider areas for long structural life.

The part of the frame below the engine and operator’s station consists of two slab-section side-frame rails, which are joined at the rear by a box-section cross member. The Slab-section 953D frame resists twisting and impact forces to provide a solid foundation for all the components it supports. Mounting points for the final drives, pivot shafts, and platform are built into each mainframe side rail.

The frame side plates are made of mild steel, which provides strength and resists shock and bending stresses. “Deep penetrating”, “Backed up” welds are used for maximum strength.

The loader tower is integral with the basic main frame. The one slab plate continues forward to become one side of the loader tower in order to provide smooth transition to loads from linkages to the mainframe rails. The loader tower provides a solid mount for lift arms, lift cylinders, and Z-bar tilt cylinder. A box-section cross member is welded below the two inboard loader tower plates to add strength. The equalizer bar, which connects the track roller frames to the main frame, is mounted below the loader tower. The result is an integrated main frame and loader tower assembly which will accommodate maximum loads capability. The engine is at the rear, where its weight serves as a “working counterweight” to balance the machine for full bucket loads without adding inefficient “dead” weight.

Breakout force is exceptionally high due to mechanical advantage of Z-bar linkage design, and hydraulic pressure applied to the head end of the tilt cylinder. Using a single tilt cylinder and linkage provides the operator a better view of the work area, bucket, and cutting edge.

The 953D linkage has fewer grease points compared to other linkage designs because every pin joint is sealed to keep grease in and dirt out. Fewer grease points and sealed pins means less downtime for maintenance allowing more working hours between servicing.

The two arms are welded into a single unit, using a weld-fabricated cross-tube. The tilt link (Dog Bone) is a single forging. The 953D linkage design combines the advantages of strength and durability with minimum structural weight, so that productivity is not penalized by excess weight in the linkage.

With the addition of certain special modifications, the capabilities of the 953D can be further expanded to handle some very harsh working conditions.

Waste Handling arrangements provide added protection and are designed to make the 953D perform well in landfills, or any waste handling applications where the machine spreads, compacts, sorts, shreds and crushes materials.

The 953D with its low ground pressure and excellent stability works well on top of loose materials, cleaning the cargo from the sides of the holds and moving it into position for the unloading system. Lifting eyes are included so that the 953D can be lifted from the dock to the hold.

For underfoot conditions that require even lower ground pressure than the standard 953D undercarriage the gauge of the machine can be widened by 300 mm (11.8 inches) and the track shoe width increased to 800mm (31.5 inches). The ground pressure is decreased to 43.3 kPa (6.3 psi).

Other arrangements beyond those shown here are available. For other custom-designed arrangements for specific applications, contact your Caterpillar Dealer.

The General Purpose (GP) bucket is designed for excellent loadability and long life in a broad range of applications such as hard bank excavating, stripping and stockpile loading. High-strength, low-alloy steel helps the bucket resist dents and abrasions. The bucket is made of high-strength, low-alloy steel plate for resistance to dents and abrasions. The shell-tine design in the bucket back and floor offers increased structural strength.

The Multi-Purpose (MP) bucket combines the performances of a standard bucket, dozer blade and clamp. The bucket provides maximum versatility combined with strength to handle a broad range of applications, such as loading, stripping topsoil, clearing, bulldozing, picking up debris and fine grading.

With the integrated trash-rack, the General Purpose Landfill (GP Landfill) bucket becomes ideal for digging, loading and carrying as well as dozing and spreading material at landfills, or loading refuse at a transfer station.

The Multi-Purpose Landfill (MP Landfill) bucket combines the versatility of a Multi-Purpose bucket with the performance of a landfill design. Constructed with a trash-rack for increased capacity, extra strength and better load retention. Ideal for applications in the harsh refuse market, whether digging or spreading material at the landfill or grasping and loading refuse at a transfer station.

Caterpillar offers several types of adapters, tips, and cutting edges, which increase bucket life and maximize performance.

The K-Series tooth system provides longer tip and adapter life, faster cycle time with greater bucket fills and reduced machine strain. Therefore, it contributes to the reduction of operating costs. Easy and convenient during the installation, this new system provides a very good response to the need of reliability and durability of such components.

Caterpillar GET offers a variety of tips to better accommodate your needs in any working environment, whether that is high impact or general-purpose applications. These and other GET options are available from your Caterpillar Dealer.

A radial ripper-scarifier is available for the 953D as an attachment. It is mounted with two pins pressed into each side of the main frame. Two cylinders raise and lower the ripper. The ripper beam has three pockets for holding ripper shanks. The six pins in the linkage do not require lubrication. The 953D ripper-scarifier is intended for ripping frozen ground, asphalt and easily ripped rock. It is not designed for hard rock.

Beyond the GP and MP buckets and the Ripper-scarifier your Cat dealer offers: Side-Dump Buckets, Landfill Buckets, Straight Trim Blades, Pallet Forks, Extendible Material Handling Arms, and Quick Couplers.

The 953D is equipped with a tiltable cab. This feature makes the maintenance and the repairs easier. By tilting the cab, you can access to the drive train and perform complete service of the hydraulic system.

• The fuel tank and the optional quick fill port are located on the right side compartment, below the cab access.
• The two maintenance-free batteries, the machine ECM and the window washer reservoir are located on the right side compartment, accessible from the ground.
• The engine compartment has large hinged openings with latches. On the door, you can clip a grease gun.

The fan and the grill swing open, providing excellent access for clean-out and maintenance. The heavy duty latched grill minimizes debris build-up.

The Engine Control ECM monitors the status of a switch that is mounted behind a cover at the rear of the machine, allowing the machine to be shut down from ground level in emergency situations.

Left engine compartment includes two spin-on hydraulic oil filters that provide filtration for the hydrostatic system. The lower part of the compartment door can be used as a step to access the shunt tank fill, the air pre-cleaner (if equipped) and allows easy cleaning of the rear window.

The cab air filter, the grouped pressure taps, the cab tilt locking bar, the optional tilt cylinder and the tool box are conveniently located below the left-side cab window.

The hydraulic tank is located in the front of the machine. It is accessible without raising the lift arms. A site gauge allows oil level check from the ground.

The fuse panel is located to the inside of the cab, on the rear right side console. It includes the ET port.

The gauge cluster and self-diagnosing Electronic Hydraulic Control (EHC) work together to warn against faults to reduce downtime.

This option allows the customer or dealer to remotely obtain machine diagnostics. Product Link provides updates on service meter hours, machine condition, machine location, and integrated mapping/route planning.

Cat field service technicians have the experience and tools necessary to service your loader on site. Technical experts at the dealership and Caterpillar can provide additional assistance to field service technicians as needed. When on-site repair isn’t enough, Cat dealerships are fully equipped to service your loader quickly.