Power Train - Engine
The twelve-cylinder, turbocharged engine is built for power, reliability, economy and with the HEUI™ fuel system, meets worldwide emissions.
Cat 3412E Diesel EngineThe four-stroke design uses long power strokes for more complete fuel combustion and optimum efficiency. High displacement and a low speed rating can help extend engine life. This engine meets U.S. Environmental Protection Agency Tier 2 emissions regulations and Stage II EU Emissions Directive 97/68/EC.
Torque RiseThe 40 percent torque rise provides high lugging force during acceleration and less down-shifting on grade or in rough underfoot conditions. The torque rise effectively matches the transmission shift points to provide maximum efficiency and faster cycle times.
Engine1) Valve Rotators2) Turbocharger3) Stellite-Faced Valves4) Steel-Backed, Copper-Bonded Bearings5) Oil Cooler6) Forged Crankshaft7) Adjustment-Free, Fuel Injection Pumps8) Hydraulic Injectors9) Forged Steel Pistons10) Full-length, Water-Cooled Cylinder Liners
Contributing to the 3412E power and reliability are:
- High pressure injection
- Full electronic control
- One piece forged steel pistons with three rings cooled by oil spray
- Copper-bonded crankshaft bearings
- Hardened crankshaft journals
- Dry-type, radial seal air cleaners with primary and secondary elements and precleaner
- Direct-electric, 24-volt starting system with 50-amp alternator and two 172-amp-hour, low maintenance, high output, 12-volt batteries
Hydraulic Electronic Unit Injector (HEUI™)The HEUI is a proven high-pressure, direct injection fuel system. This system electronically monitors operator and machine inputs to optimize engine performance. HEUI is unique in its ability to independently control injection pressure over the entire engine operating range. This allows complete control over injection timing, duration, performance and efficiency. Rate shaping technology modifies the heat release characteristics of the combustion process for significant decreases in sound and emission levels. Exhaust smoke is significantly reduced through precise, electronic control of fueling limits and injection timing.
Electronic Control Module (ECM)The ECM monitors key functions and logs critical indicators. The Electronic Technician can access this diagnostic information for easier maintenance and repair.
Power Train - Transmission
The Cat seven-speed, power shift transmission gets the job done smoothly and quickly.
TransmissionThe Cat seven-speed, power shift transmission, matched with the direct-injection 3412E diesel engine provides constant power over a wide range of operating speeds.
- Seven speeds forward, one reverse
- Torque converter driven in reverse
- First gear has both torque converter drive and direct drive
- Second through seventh gears are direct drive
- Single-lever shift control provides automatic shifting in all gears up to the one selected by the control lever
- Each shift is individually modulated for maximum smoothness
- Separate hydraulic circuit with cooler
- Electronic control has built-in diagnostics and fault memory, event memory and programmable features
- Control throttle shifting
- Economy shift mode
1) Lock-up Torque Converter
Combines the maximum rimpull and cushioned shifting of torque converter drive with the efficiency and performance of direct drive.
- Engages at approximately 6.9 km/h (4.3 mph), delivering more power to the wheels
- Lock-up clutch quickly releases and re-engages during shifts, maintaining power wind-up, improving transmission life and increasing operator comfort
2) Planetary Power Shift Transmission
Utilizes a modulating pressure valve to regulate clutch pressure rise and fall to ease clutch engagement. This reduces shock loads on power train components. Features include:
- Large diameter clutches and robust planetary gears and bearings
- Patented rotating clutch pressure seals minimize drag losses and improve reliability
- 35 percent gear splits between all gears match Cat engine design for optimum use of engine power with minimized shifting and torque converter use
3) Final DriveFinal drive and differential torque multiplication of 17.48:1 further reduces stress on the drive train.
AxlesFull floating axles are shot-peened to relieve internal stresses and increase durability. Rolled splines also provide increased service life.
Wheel and RimsCast rear wheels and Cat center-mount rims are mounted using studs and nuts to minimize maintenance and maximize durability.
Transmission Chassis Controller (TCC)
TCC uses electronically transferred engine rpm data to execute shifts at preset points for optimum performance and efficiency. This integration allows:
- Programmable top gear limit
- Control throttle shifting
- Directional shift management
- Neutral coast inhibitor
- Economy shift mode
IntegrationThe Caterpillar power train integration provides increased component life and operator comfort.
Engine/Power Train Integration
Combining the electronic Engine Control Module (ECM) with the Caterpillar Transmission Chassis Controller (TCC) allows critical power train components to work more intelligently.
Integration1) Electronic Technician2) Cat Data Link System3) Engine Control Module4) Engine5) Transmission Chassis Controller6) Automatic Retarder Control, Traction Control System and Integrated Brake Controller7) Caterpillar Electronic Monitoring System8) Transmission9) Oil-Cooled Brakes
Cat Data LinkThe Cat Data Link electronically integrates the machine's computer systems, which allows communications and provides the following benefits:
• Elevated Idle Neutral Coast InhibitorHelps prevent the transmission from shifting to neutral at speeds above 6.5 km/h (4 mph).
• Body-up Shift InhibitorHelps prevent the transmission from shifting above a pre-programmed gear without the body fully lowered.
• Event Memory
Records machine management data that can be accessed using the Electronic Technician. Recorded information includes:
- Shift histograms
- Operator-induced events
- Lock-up clutch counter
- Machine overspeed
- Transmission overspeed
Electronic Technician (ET)
The electronic engine and transmission controls provide exhaustive diagnostic capability for service technicians. The ability to store both active and intermittent indicators will simplify problem diagnosis and reduce total repair time, resulting in improved mechanical availability and lower operating cost.
- ET accesses data stored in the engine and transmission controls via the Cat Data Link System.
- ET displays the status of all engine parameters including throttle position, timing and fuel flow.
- ET replaces 13 mechanical tools to perform functions like cylinder cutout checks, injector solenoid tests and timing calibration.
Caterpillar Electronic Monitoring System (CEMS)CEMS allows the operator to view requested information and utilizes a three-category warning system to alert the operator to abnormal machine conditions.
Optional AttachmentsCaterpillar offers optional attachments that integrate with the Cat Data Link System.
Oil-Cooled, Rear Disc Brakes
Rear braking lets the operator concentrate on the haul road.
Brakes1) Parking/Secondary Piston2) Service/Retarding Piston3) Friction Discs4) Steel Plates5) Actuating Springs6) Cooling Oil In7) Cooling Oil Out
Multiple Disc BrakesCaterpillar forced oil-cooled, multiple disc brakes are continuously cooled for exceptional, fade-resistant braking and retarding. The optional ARC and TCS utilize the oil-cooled rear brakes to enhance truck performance and increase productivity.
Oil-Cooled Disc BrakesAre designed and built for reliable, adjustment-free operation providing superior performance and service life in comparison to shoe-type and dry-disc systems.
Oil FilmAn oil film prevents direct contact between the discs. Absorbing the braking forces by shearing oil and carrying heat away, this design extends brake life.
Secondary BrakingSpring-applied, hydraulically released, oil-cooled disc brakes are located on the rear axle. The front brakes will activate as part of the secondary system, even if switched out of service.
Parking BrakesSpring-applied, hydraulically released parking brakes use wet disc brakes in the service system. A toggle switch activates the parking brake.
PistonsA Caterpillar patented, two-piston design combines the service, secondary and parking brakes, along with retarding functions.The primary piston hydraulically actuates both service and retarding functions. The secondary piston is spring-applied and held in the disengaged position by hydraulic pressure. If hydraulic system pressure drops below a certain level, the spring-applied secondary piston automatically applies the brakes.
Integrated Braking Control (IBC)
Electronically combines Automatic Retarding Control (ARC) and the Traction Control System (TCS) into one integrated control system.
Automatic Retarder Control (Optional)The ARC electronically controls braking on grade to maintain approximately 2,230 rpm (engine rpm is adjustable from 2,150-2,300 rpm in increments of 10 rpm). ARC is deactivated when the operator applies the brakes or throttle.
Engine Overspeed ProtectionWith the accelerator depressed and/or ARC turned off, ARC will automatically activate at 2,475 rpm to help avoid potentially destructive and often costly engine overspeeds.
- Increased operating efficiency with faster downhill speeds. By maintaining consistently higher engine speeds, average truck speed will be higher than a manually controlled truck.
- Excellent controllability and reduced operator effort. Automatic brake modulation provides a smoother ride over manual modulation, allowing the operator to focus more on truck operation down the haul road.
- Improved component life, optimized system cooling capability and reduced torque fluctuations result from ARC's precision.
- Faster troubleshooting and diagnosis with self-diagnostic capability and the ability to communicate with ET through the Cat Data Link System.
- Operator awareness through electronic integration and CEMS, alerting the operator to overspeed conditions and critical machine functions.
Traction Control System (Optional)Monitors wheel slip so if it exceeds the set limit, the oil-cooled disc brakes are automatically applied to slow the spinning wheel.
Operator AwarenessAn on-dash indicator shows the operator that TCS is engaged.
Differential ActionUtilizes normal differential action to provide superior maneuvering in poor underfoot conditions. Also reduces tire scuffing as compared to positive lock differentials used on other systems.
TorqueTCS divides torque equally to reduce stress created on final drives and axles when torque is transferred to one side.
System Back-upShould sensors fail, the normal differential action is still available to maintain control and steering.
The backbone of the Cat off-highway truck.
Box-Section DesignThe 773E frame uses a box-section design, incorporating 20 castings in high stress areas with deep penetrating and continuous wrap-around welding. Mild steel, which provides flexibility, durability and resistance to impact loads even in cold climates is used throughout.
CastingsCastings have large radii with internal reinforcing ribs to dissipate stress. Castings move welds to lower stress areas and provide two to three times the strength of equivalent sized fabricated structures.
- Integral front bumper
- Front box beams for suspension cylinder and ROPS support
- Box-section rear crossmember for body and ROPS support with attachment points for maintenance platform and rear engine hood hinge support
- Castings provide additional strength in critical stress areas
- Mild steel plates (290 MPa [42,000 psi} minimum yield strength) and castings (241 MPa [35,000 psi] minimum yield strength) provide flexibility, durability and easy field maintenance
Frame ServiceabilityThe box-section frame allows simple access to power train components. This open design reduces overall removal and installation time, lowering repair costs. Transmission access is excellent under the raised and pinned body. Repairs can be made without preheating in ambient temperatures above 16° C (60° F) using readily available welding supplies.
Rollover Protection Structure (ROPS)The ROPS attaches securely to four castings welded into the frame.
Suspension SystemDesigned to dissipate haul road and loading impacts for extended frame life. Four independent, self-contained, oil pneumatic, variable-rebound, suspension cylinders absorb shocks. Rear cylinders allow axle oscillation and absorb bending and twisting stresses. Front cylinders, mounted to the frame, serve as steering kingpins, providing excellent maneuverability and reduced maintenance. Caster and camber are preset.
Truck Body Options
Caterpillar builds a variety of rugged, durable bodies to perform in the toughest applications.
Design773E bodies are designed to handle a variety of material densities. Maximum payload is reached in three to five passes from a matched Cat loader in 1700 kg/m3 (2,900 lb/yd3) material and higher.
Sidewall and Floor JunctionsAre joined by five-sided beams to resist impact loading and sustained hauling stresses.
Box-Section BeamsOffer increased durability in the floor, sidewalls, top rail, corner and cab canopy areas.
400 Brinell SteelWear surfaces provide excellent wear resistance and are easily welded without preheating procedures.
Two-Stage Hoist CylindersProvide fast dump cycle times of 9.5 seconds for raise and 12.5 seconds for lower.
Standard BodyComes exhaust heated with options including a full-time muffler or exhaust diverter.
Custom AttachmentsIncluding tail extensions, liner packages, sideboards and other custom designs are offered to help ensure rated payload.
1) Dual-Slope BodyOffers the lowest cost-per-ton option in most construction and mining applications.
Dual-Slope Body PerformanceEfficient under most haul road conditions, but its strength comes from higher levels of production in sites with rough haul roads and steeper grades.
Body Floor ConstructionUses an eight degree "V" bottom for increased load retention, a low center of gravity and reduced shock loading. It also aids in centering the load.
18 Degree Ducktail and 9 Degree Forward Body SlopeRetains the load on grades up to 15 percent and higher. This design also helps maintain proper load distribution.
2) Flat Floor Construction and Mining BodyOffers excellent load retention on grades up to 12 percent and on smoother haul road conditions.
Body Floor ConstructionUses a 12 degree single slope, offering excellent wear characteristics and uniform dumping into hoppers, crushers and feeders.
Control ease and comfort maximize productivity.
773E Operator StationRated highly by operators with everything needed for top performance located at the operator's fingertips.
1) Wraparound Dash PanelOffers an easy line-of-sight arrangement, using LED backlit rocker switches.
2) Caterpillar Contour Series Air Suspension SeatStandard and fully adjustable, including an adjustable right-hand armrest.
3) Tilt-Telescoping Steering WheelWith ergonomic grip improves comfort and control. Low effort steering system and ergonomically designed retarder lever reduce operator fatigue. Also includes an enhanced turn signal lever with high beam actuator and electric windshield wiper controls.
4) Transmission ConsoleHas LED backlit gear numbers and ergonomic shift knob.
5) VisibilityExceptional all-around viewing area reduces fatigue and improves productivity.
6) Integral, Sound-Suppressed ROPS/FOPS CabIs resiliently mounted providing a quiet, protected work environment. The cab is radio-ready with speakers, wiring harness, antenna and mounting bracket.
7) Front Brake Cut-Out SwitchIncreases front brake component life.
8) Large Storage Compartment0.10 m3 (3.5 ft3) of storage space is located under the trainer's seat.
9) Trainer's SeatIncludes back rest and retractable seat belt.
10) Caterpillar Electronic Monitoring System (CEMS)
Provides critical data. The system features three separate displays:
- Four-gauge cluster with coolant temperature, oil temperature, brake air pressure, fuel level
- Tachometer, digital speedometer, actual gear indicator
- Message center module
11) Standard Heater and Optional Air ConditionerIncludes four-speed fan and nine vents.
12) Foot PedalsErgonomically designed for increased operator comfort.
13) Electric Power WindowFor simplified operation.
14) Electrohydraulic Hoist LeverIs fingertip actuated and provides low impact body-down snubbing.
15) Truck Production Management System (TPMS) (Optional)
Provides payload and cycle time data.
- Cat developed technology utilizes strut pressure sensors and an on-board microprocessor to determine payload weight
- Accurate under normal loading to within ± five percent over a normal operating shift
- Delivers consistent accurate payloads and improves efficiency by minimizing overloading and underloading
- On-board computer stores 1,400 cycles for further analysis of payload weight, cycle segment times, cycle segment distances and actual clock time and date of each cycle- External lights signal loading tool operator when payload is reached- Internal troubleshooting and fault recording for easier maintenance
Serviceability/Total Customer Support
Purchase of a Caterpillar machine includes a total commitment to customer support.
Cat QuickEvac™ SystemIs an exclusive Caterpillar on-board engine oil evacuation and prelubrication system.
Automated Engine Oil ChangeA new, state-of-the-art, on-board system evacuates engine sump in less than two minutes and allows for purge of oil filters prior to removal, minimizing oil spills. It delivers new oil through primary filters for filtered protection and ensures new filters are correctly filled following routine oil change.
Contamination ControlEnvironmentally efficient, clean oil changes are ensured since engine sump is evacuated directly into PM trucks or waste containers with flush faced, quick disconnects for fast evacuation and fill. This eliminates handling of waste oil, minimizes chances of oil spillage and enhances Contamination Control efforts by ensuring complete filtration of new oil on engine refill.
Complete Engine PrelubricationProvides engine oil pressure prior to engine cranking. Reduces engine dry start wear and risk of cold starts for increased protection of key components. Also provides expanded low temperature range for 15W40 motor oils.
Improved Serviceability and Machine AvailabilityReduces time to complete engine service (changing engine oil, oil filters, fuel filter, air cleaner) by as much as 30 to 50 percent. Improves the ability to schedule engine services at prescribed hours, allows for servicing during normal working hours and integrates easily with PM trucks to further reduce total cycle time of engine service.
Machine PlatformProvides access to air tanks, brake master cylinder and make-up tank; engine oil level; air filters; steering hydraulic tanks; and battery compartment.
Ground Level Battery DisconnectFacilitates safe, convenient servicing and maintenance.
On-Board DiagnosticsWith CEMS, provides the machine operator with a three-category warning system and quick access to stored diagnostic data.
Off-Board DiagnosticsWith ET, allows service technicians access to stored diagnostics data reducing downtime and lowering operating costs. ET stores engine parameter information such as timing, throttle position and fuel flow. Transmission data is available through ET via access to the Cat Data Link System.
Radial Seal FiltersAre easy to change, reducing air filter maintenance times.
Vertical, Spin-On FiltersProvide for simplified servicing.
Quick Coupler Pressure TapsLocated in all hydraulic systems provide clear, quick pressure checks. S·O·SSM oil analysis points make oil sampling quick, clean and easy.
Sealed Electrical ConnectorsLock out dust and moisture. Color-coded wiring is standard for the entire Cat product line.
Machine Management Service
Cat dealers help manage equipment investments with:
- Vehicle systems analysis to help match the right machine to the job
- Preventative maintenance programs
- S·O·S oil analysis and technical analysis programs
- Repair option analysis
- Training for operators and mechanics
- TPMS data analysis
Parts AvailabilityThe Caterpillar worldwide computer network locates parts instantly to minimize machine downtime.
Literature SupportCaterpillar manuals are easy to use and help provide the full value of an equipment investment.
The 773E is designed for versatility.
Machine Configuration OptionsCaterpillar offers a variety of machine configuration options to help meet customer needs.
Body OptionsInclude a full line of standard and custom designs based on specific customer preference, material density, loading tool and site conditions.
Tire OptionsA full line of tire options, representing various manufacturers, is offered by Caterpillar. To maximize performance and life for specific applications.
Give the customer options to tailor trucks for specific application requirements, including:
- Truck Production Management System
- Automatic Retarder Control
- Traction Control System
- Custom product offerings
- Muffler/exhaust diverter
System ApproachThe Caterpillar system approach means increased efficiencies through common design. Haul trucks, loaders, excavators, tractors, engines for generator sets and pumps - all designed by Caterpillar - use common components, parts and design. Commonality reduces customer parts stock, improves parts availability, reduces training/maintenance and improves diagnostics. This system approach adds up to lower costs-per-ton. Dealer support is available to address customer needs regardless of the component.
Caterpillar Product Analysis Team (PAT)Combined with Caterpillar software programs can assist customers with detailed, application evaluation.
Designed to work as part of a system, the 773E is best matched to the following Caterpillar loaders:
- 988G - five pass/match
- 990 Series II - three pass/match
- 5080 - six pass/match