Hydraulics

Main Pumps

The hydraulic system includes three pumps with an independent swing circuit. The hydraulic circuit utilizes a load-sensing system to ensure high hydraulic system efficiency and excellent productivity with little hydraulic loss. • Large, heavy-duty main pumps and a separate swing pump provide quick cycle times during multi-function operation.

Reverse Swing Dampening Valve

Swing dampening valves reduce swing wag and produce smooth swing stops.

Advanced Features

The following are hydraulic system features of the 374D L:

The electric re-generation system is incorporated into the hydraulic system to improve hydraulic efficiency and lower fuel consumption.

The main pump flow has increased 10 percent to provide shorter cycle times.

The main implement pressure has been increased 9 percent. This also provides shorter cycle times with higher digging forces and increased bucket fill factors.

Stick cylinder diameter for mass and reach configurations has been increased along with the bucket cylinder diameter on the reach stick. These increases produce 17 percent higher digging forces.

These features all combine to provide a significant increase to machine productivity.

Proportional Priority Pressure Compensation (PPPC) Hydraulics

Load-sensing, PPPC system, with Caterpillar developed electronic actuation, provides high efficiency and excellent controllability.

Cylinder speed is directly related to operator’s movement of joystick from feathering to full speed.

Flow to cylinders during multifunctional operation is directly controlled by the operator and is not dependent on loads.

Controller reduces pump output to minimum to save power when joysticks are in neutral position.

Operator Station

Cab Design

The spacious cab provides good visibility and ergonomics. The monitor is a full-color graphical display which provides the operator with easy-to-read, comprehensive machine information. The cab provides a comfortable environment for the operator to work in and helps reduce fatigue over long periods.

Hydraulic Activation Control Lever

The hydraulic activation control lever deactivates hydraulic functions during engine start-up and prevents unintentional machine operation.

Cab Exterior

Utilizes thick steel tubing along the bottom perimeter of the cab, improving the resistance of fatigue and vibration. The cab structure allows the FOGS to be bolted directly to the cab, at the factory or as an attachment.

Cab Mounts

The cab shell is attached to the frame with viscous rubber cab mounts, which dampen vibrations and sound levels while enhancing operator comfort.

Additional Features

The 374D L operator station has many features for operator comfort:

1. Premium KAB seats with adjustable height consoles.
2. A rear view camera is offered as an attachment. The monitor functions as the display screen for the camera, providing added safety for the operator and surrounding work area.
3. HID (High Intensity Discharge) lights are available as an attachment with time delay for the boom and cab lights.
4. A two-way radio ready option is available.
5. Automatic climate control for the for air conditioner, heater and defroster.
6. Fuel consumption can be displayed numerically on the monitor.
   Engine

   Cat C15 Engine

   The Cat C15 engine with mechanically actuated electronic fuel injection (MEUI™) powers the 374D L. The C15 has ACERT Technology, a series of Caterpillar engineered innovations which provide advanced electronic control, precision fuel delivery and refined air management compliance.
   

   Increased Power

   The maximum power is 355 kW (476 hp), which is 18 percent more than the 365C. Power Management System (PMS) is now standard to better manage productivity and fuel economy.
   

   Improved Fuel Efficiency

   The 374D L fuel maps provide additional power and performance with optimized fuel consumption through flexible power settings incorporated into ADEM™ controller.
   

   Improved Reliability

   The titanium-aluminum alloy rotor in the turbocharger improves reliability/durability and contributes to faster response of the turbocharger.
   

   Hydraulic Cooling Fan

   The 374D L uses a variable speed, hydraulically-driven fan for quieter operation and reduced fuel consumption during cooler ambient conditions.
   

   Reversible Fan

   A reversible fan option is offered as an attachment. The reverse function is operated through the monitor. By selecting this function, the fan rotates in the opposite direction for a preset time to help clean the cooling package for increased uptime and reduced service cost.
   
   
   
   Control System

   Monitor Display Screen

   The monitor is a full color, 400 × 234 pixels Liquid Crystal Display (LCD). A master caution lamp blinks ON and OFF when one of the critical conditions below occurs:
   1. Engine oil pressure low
   2. Coolant temperature high
   3. Hydraulic oil temperature high
   The monitor display screen is divided into four areas: clock and throttle dial, gauge, event display and multi-information display.
   

   Gauge Display

   Three analog gauges, fuel level, hydraulic oil temperature and coolant temperature are displayed in this area.
   

   Electronic Joysticks

   Electronic joysticks provide features not possible with hydraulic pilot valves:
   1. Eliminate pilot lines in cab for quieter operation
   2. Simple pattern change through the monitor
   
   

   Operator Gain/Response

   This is used to suit the operator preference or application needs.
   1. Quicker for fast response
   2. Slower for more precision
   3. Contains three preset settings with 21 control perception patterns available
   
   

   Pattern Control Changer

   The standard hand control pattern changer can be accessed through the monitor, to utilize either the standard excavator control pattern (SAE) or Backhoe Loader pattern (BHL).
   

   Alternator

   The alternator is 24 volt with 75 amp capacity and is driven by a serpentine belt off the front pulley. A snorkel pulls cool, clean air from the outside for increased service life.
   

   Product Link™

   Product Link on the 374D L is standard in some markets and available as an option in others. Product Link transmits diagnostic information from the machine back to Caterpillar, Cat dealers and customers.
   
   Structures

   Variable Gauge Undercarriage

   The long variable gauge undercarriage is standard, providing a wide, stable base for operating, or a narrow gauge for reduced shipping width. The undercarriage gauge in working position has been increased by 160 mm (6.3 in) for improved stability.
   

   Upper Frame

   The upper frame is designed for maximum durability and efficient use of materials. The boomfoot, skirt and counterweight mounting area have been strengthened for longer service life and increased durability. The outer frame utilizes curved, die-formed side rails for excellent uniformity and strength through length. The box section channels improve upper frame rigidity under the cab, while the boom tower and one-piece main rails are constructed of solid, high-tensile strength steel plates.
   

   Catwalk

   The catwalk width has been increased by 110 mm (4.3 in) from the 365C L. Catwalks are provided on both sides of the skirt for easy access of the maintenance points. Slip resistant plates are used on the full length of the catwalks.
   

   Cross Roller Bearing

   The 374D L swing bearing is a cross roller type, with 54 mm (2.13 in) diameter rollers. The cross rollers have a much greater contact area than ball bearings particularly during boom down operation, providing increased stability and reducing machine pitching.
   

   Track Roller Frames

   The track roller frame is made of thick, steel plate that is bent into a U-shape and welded to the bottom plate to create a box structure for increased rigidity and impact resistance.
   
   Undercarriage

   Undercarriage

   The undercarriage supports the swing bearing and upper structure and is the link that transmits the reaction forces from digging to the ground. The strength of the undercarriage plays a major factor in machine stability and durability.
   

   Track Roller Frame

   The track roller frame has been improved by installing a longer stroke recoil spring and lowering the front idler. The longer recoil spring increases the stroke by 25 percent while improving durability and service life of the undercarriage. The offset idler increases the stability of the machine while working over the front.
   

   Positive Pin Retention 2 (PPR2)

   Track links with the PPR2 are provided as standard on the 374D L. The PPR2 track link is designed to prevent looseness of the track pin in the track link and to reduce stress concentrations, particularly in severe underfoot conditions. The PPR2 system eliminates pin walking for increased service life.
   

   Carrier Rollers

   The carrier rollers use a floating “Duo-Cone™” seal. The Duo-Cone seal protects the moving parts in the carrier roller from water and dirt and makes lubrication maintenance-free.
   
   Front Linkage

   Front Linkage

   Cat Excavator booms and sticks are built for performance and long service life.
   1. Castings and forgings are used at high stress areas such as boom nose, boom foot, boom cylinder and stick foot.
   2. All booms and sticks are stress-relieved for optimal life and durability, while minimizing weight for improved performance.
   3. All booms and sticks are ultrasonic inspected.
   
   

   Bucket Linkage

   Two bucket linkages are available for the 374D L. Both linkages are available with or without a lifting eye on the power link.
   1. The VB2 bucket linkage is for use with the reach sticks and VB2-family buckets
   2. The WB2 bucket linkage is for use with the mass sticks and WB2-family buckets
   
   

   Boom Construction

   374D L booms feature a large cross-section to improve strength and reduce weight. Baffle plates reinforce the boom interior for higher rigidity. Booms are designed for strength and maximum payload.
   

   Stick Construction

   Sticks are made of high-tensile strength steel in a box-section design, making them strong and light. All sticks are reinforced with a thick baffle plate for added rigidity. The connection between stick and boom is made of forged steel, and a thick steel plate is used at the bucket connecting location for increased strength and rigidity at load-bearing points. An additional wear plate is added to the working side of the stick for protection. All mass sticks include additional wear bars on the working side to protect the structure during operation. There are four reach sticks and two mass sticks available to meet your needs.
   

   Linkage Pins

   Bucket cylinder pin and idler to stick pin diameters for the reach boom have been increased. The pins have thick chrome plating for high wear resistance and long life.
   
   Buckets and Teeth

   Optimized Package

   Caterpillar offers a wide range of buckets, each designed and field tested to function as an integral part of your excavator. All Cat Buckets feature K Series™ GET (Ground Engaging Tools). Buckets are available in four levels of durability and are built to take full advantage of the machine’s power.
   

   General Duty (GD)

   General Duty buckets are designed for use in low impact, lower abrasion materials such as dirt, loam and mixed compositions of dirt and fine gravel.
   

   Heavy Duty (HD)

   Heavy Duty buckets are the most popular and a good “centerline” choice. This bucket style is a good starting point when application conditions are not known. Heavy Duty buckets are designed for a wide range of impact and abrasion conditions including mixed dirt, clay and rock.
   

   Severe Duty (SD)

   Severe Duty buckets are designed for higher abrasion conditions such as shot granite. When compared to the Heavy Duty bucket, wear bars and wear plates are substantially thicker and larger for added protection.
   

   Extreme Duty (XD)

   Extreme Duty buckets are designed for very high abrasion conditions such as granite quarries. Corner shrouds have been added and side wear plates are larger for added protection.
   
   
   
   Work Tools

   Increase Machine Versatility

   The Cat combination of machine and tool provides a total solution for just about any application. Work tools can be mounted directly to the machine or a quick coupler can be added, making it quick and easy to release one work tool and pick up another.
   

   Couplers

   Caterpillar offers two quick coupler styles: dedicated and pin grabber. Each allows quick tool changes.
   

   Center-Lock™ Pin Grabber Coupler

   Center-Lock is the Cat pin grabber style coupler and features a patent pending locking system. A highly visible secondary lock clearly shows the operator when the coupler is engaged or disengaged from the bucket or work tool.
   

   Work Tools

   An extensive range of Cat Work Tools for the 374D L includes buckets, hammers, grapples, shears, multi-processors and rippers. Each are designed to optimize the versatility and performance of your machine. Cat Work Tools and couplers are ready to work in a variety of applications, such as site and structure demolition, debris clean-up, truck loading, scrap processing, breaking road surfaces and bed rock.
   

   Hydraulic Kits

   Caterpillar offers field-installed hydraulic kits designed to simplify the process of ordering and installing the right kit. Modular kit designs integrate Cat Work Tools with Cat Hydraulic Excavators. Every kit is easy to install. Hoses are pre-made, tubes are pre-bent and pre-painted and there are comprehensive instructions.
   
   Environment

   Emissions

   ACERT Technology is a differentiated technology that reduces emissions at the point of combustion. The technology capitalizes on proven Caterpillar leadership in three core engine systems: fuel, air and electronics.
   

   Electro Magnetic Compliance

   The 374D L meets the following EMC (Electro Magnetic Compliance) requirements:
   1. ISO 13766 Earth Moving Machinery – Electromagnetic compliance
   2. EU Directive 89/336/EEC
   3. Aus EMC Framework
   
   

   Fluid Management

   Several serviceability elements are designed into the 374D L to limit fluid spillage while performing routine maintenance.
   

   Ecology Drains

   Ecology drains are provided for the fuel and hydraulic tanks, allowing fluids to be captured in a container when draining the tanks.
   
   
   
   Service and Maintenance

   Service Intervals

   Long service intervals reduce maintenance costs. Engine oil, oil filter and fuel filters are at 500 hours.
   

   Oil Sample and Pressure Ports

   Oil sample and pressure ports provide easy checking of machine condition and are standard on every machine.
   

   Hydraulic Capsule Filters

   The return filters or capsule filters for the hydraulic system are located beside the hydraulic tank. The filter elements are removable without spilling hydraulic oil.
   

   Service Points

   Service points are centrally located with easy access to facilitate routine maintenance.
   

   Pilot Hydraulic System Filter

   Pilot hydraulic system filter keeps contaminants from the pilot system and is located in the pump compartment.
   

   Remote Greasing Block

   A concentrated remote greasing block on the boom delivers grease to hard-to-reach locations.
   

   Radial Seal Cleaner

   Radial seal main air cleaner with precleaner has a double-layered filter element for more efficient filtration. No tools are required to change the element.
   

   Fuel-Water Separator

   The water separator removes water from fuel, even when under pressure, and the water level can be monitored in the cab.
   
   
   
   Complete Customer Support

   Product Support

   Cat dealers utilize a worldwide computer parts network to minimize machine downtime. Save money with Cat Remanufactured components.
   

   Machine Selection

   Make detailed comparisons of machines you are considering. What are job requirements and machine attachments? What production is needed? Your Cat dealer can provide recommendations.
   

   Purchase

   Consider financing options and day-to-day operating costs. Look at dealer services that can be included in the machine’s cost to yield lower owning and operating costs over time.
   

   Customer Support Agreements

   Cat dealers offer a variety of product support agreements and work with you to develop a plan to meet specific needs. These plans can cover the entire machine, including attachments, to help protect your investment.
   

   Operation

   Improving operating techniques can boost your profits. Your Cat dealer has videos, literature and other ideas to help you increase productivity, and Caterpillar offers certified operator training to help maximize the return on your investment.
   

   Maintenance Services

   Repair option programs guarantee repair costs up front. Diagnostic programs such as Scheduled Oil Sampling, Coolant Sampling and Technical Analysis help you avoid unscheduled repairs.
   

   Replacement

   Repair, rebuild or replace? Your Cat dealer can help you evaluate the cost involved so you can make the right choice.
   
   
   

Engine Model Cat C15 ACERT™ (ATAAC)
Cat C15 ACERT™ (ATAAC)Net Flywheel Power 476 hp
355 kWNet Power – ISO 9249 476 hp
355 kWNet Power – SAE J1349 476 hp
355 kWNet Power – EEC 80/1269 476 hp
355 kWBore 5.4 in
137 mmStroke 6.75 in
171 mmDisplacement 928 in3
15.2 LWeights
Operating Weight 156819 lb
71132 kgOperating Weight – Long Undercarriage 156819 lb
71132 kgTrack
Standard w/Long Undercarriage 36 in
900 mmOptional for Long Undercarriage 26 in
650 mmNumber of Shoes (each side) – Long Undercarriage 47
47Number of Track Rollers (each side) – Long Undercarriage 8
8Number of Carrier Rollers (each side) 3
3Optional for Long Undercarriage 30 in
750 mmSwing Mechanism
Swing Speed 6.4 RPM
6.4 RPMSwing Torque 158428 lb ft
214.8 kN·mDrive
Maximum Travel Speed 2.6 mph
4.1 km/hMaximum Drawbar Pull – Long Undercarriage 110718 lb
492.5 kNHydraulic System
Main System – Maximum Flow (Total) 232 gal/min
880 L/minSwing System – Maximum Flow 95 gal/min
360 L/minMaximum Pressure – Equipment – Normal 5076 psi
35000 kPaMaximum Pressure – Travel 5076 psi
35000 kPaMaximum Pressure – Swing 4264 psi
29400 kPaPilot System – Maximum Flow 23 gal/min
87 L/minPilot System – Maximum Pressure 600 psi
4120 kPaBoom Cylinder – Bore 7.5 in
190 mmBoom Cylinder – Stroke 70.6 in
1792 mmStick Cylinder – Bore 8.3 in
210 mmStick Cylinder – Stroke 83.4 in
2118 mmVB2-Family Bucket Cylinder – Stroke 56.8 in
1443 mmVB2-Family Bucket Cylinder – Bore 7.5 in
190 mmWB2-Family Bucket Cylinder – Stroke 57.4 in
1457 mmWB2-Family Bucket Cylinder – Bore 7.9 in
200 mmService Refill Capacities
Fuel Tank Capacity 247 gal
935 LCooling System 25 gal
95 LEngine Oil 17 gal
65 LSwing Drive (each) 3.2 gal
12 LFinal Drive (each) 4 gal
15 LHydraulic System (including tank) 186 gal
705 LHydraulic Tank 95 gal
360 LSound Performance
Performance ANSI/SAE J1166 OCT98
ANSI/SAE J1166 OCT98Standards
Brakes SAE J1026 APR90
SAE J1026 APR90Cab/FOGS SAE J1356 FEB88, ISO 10262
SAE J1356 FEB88, ISO 10262Benefits & Features