637G Wheel Tractor Scraper

637G Wheel Tractor Scraper

360° Exterior View

Quick loading, high travel speeds and the ability to load and dump on the run yield fast cycle times, allowing Caterpillar Wheel Tractor-Scrapers to consistently deliver high productivity ...

Tractor Engine

Flywheel Power - Tractor/Scraper
373 kW (500 hp) / 211 kW (283 hp)
Net Power
345 kW (462 hp) / 373 kW (500 hp)
Gross Power - Gears 1-2
Gross Power - Gears 3-8
Net Power - Gears 1-2
Net Power - Gears 3-8

Scraper Bowl

Scraper Capacity - Heaped
Rated Load
Capacity - Struck
Depth of Cut - Maximum
Width - Cut - To Router Bits
Ground Clearance - Maximum
Cutting Edge Thickness
Hyd. Penetration Force - 637G
Depth of Spread - Maximum
Apron Opening
Apron Closure Force


Top Speed - Loaded
1 Forward
2 Forward
3 Forward
4 Forward
5 Forward
6 Forward
7 Forward
8 Forward


Tractor Engine
Cat C18 ACERT™
Scraper Engine

Scraper Engine

Net Power
198 kW (266 hp) / 211 kW (283 hp)
Gross Power - Gear 1
Gross Power - Gears 2-4
Net Power - Gear 1
Net Power - Gears 2-4

Weights - Push-Pull

Total Shipping
Tractor Shipping
Scraper Shipping
Total Operating - Empty
Front Axle
Rear Axle
Total Operating - Loaded
Front Axle - Loaded
Rear Axle - Loaded


Width - Overall Machine
Width - Tractor
Width - Rear Tire Center Lines
Width - Inside of Bowl
Width - Outside Rear Tires
Width - Outside Bowl - Shipping Width
Height - Overall Shipping
Height - Top of Cab
Ground Clearance - Tractor
Front of Tractor to Front Axle
Axle to Vertical Hitch Pin
Height - Scraper Blade Maximum
Wheel Base
Length - Overall Machine
Rear Axle - Rear of Machine
Bail Length - Maximum (Push-Pull)
Extended Push Block (Push-Pull)

Service Refill Capacities - Tractor

29gal (US)
Hydraulic Reservoir
50.2gal (US)
Final Drive - Each
6.1gal (US)
39gal (US)
Cooling System
29gal (US)
11.9gal (US)
Fuel Tank - 637G
335gal (US)
Wheel Coolant - Each
19.8gal (US)
Windshield Washer
1.5gal (US)


Width - 180° Turn
Width - 180° Turn - Right
Steering Angle - Right
Steering Angle - Left
Hydraulic Output

Weights - Standard, Tandem

Total Shipping
Tractor Shipping
Scraper Shipping
Total Operating - Empty
Front Axle
Rear Axle
Total Operating - Loaded
Front Axle Weight - Loaded
Rear Axle - Weight - Loaded

Service Refill Capacities - Scraper

Fuel Tank - 637G
335gal (US)
7.9gal (US)
19gal (US)
3.2gal (US)
Final Drive - Each
5gal (US)
Wheel Coolant - Each
19.8gal (US)
Cooling System
20gal (US)

Transmission - 637G

1 Forward
2 Forward
3 Forward
4 Forward
5 Forward
6 Forward
7 Forward
8 Forward


Bowl Cylinder Bore
Bowl Cylinder Stroke
Apron Cylinder Bore
Apron Cylinder Stroke
Ejector Cylinder Bore
Ejector Cylinder Stroke
Steering Circuit
Scraper Circuit
Cushion Hitch Circuit
Secondary Steering Circuit
Relief Valve - Steering Circuit
Relief Valve - Implement Circuit
Compensator Settings - Cushion Hitch Circuit

Power Train - Engine

C18 Tractor Engine

The tractor for the 637G is powered by the C18 engine with ACERT Technology. The large displacement and high torque rise allow the scraper to cut through tough material. Matched to the high efficiency torque converter and electronically controlled power shift transmission, it will provide years of dependable service.

C-9 Scraper Engine

The 637G is tandem-powered, adding a Cat C9 engine with ACERT™ Technology for the scraper. The C9 gives the 637G exceptional power and fuel efficiency unmatched in the industry for consistently high performance in all applications.

Dual Horsepower

C series engines have dual horsepower capability with the low power setting in torque converter drive and the high power setting in direct drive. If the auger is engaged while the machine is in torque converter drive, the machine automatically goes to the high power setting.

Mechanical Electronic Unit Injection (MEUI

The MEUI system with variable shaped injection patterns provides for optimum combustion based on altitude and temperature. The Cat MEUI fuel system is a highly evolved fuel system with a proven record of reliability in the field. The system combines the technical advancement of an electronic control system with the simplicity of direct mechanically controlled unit fuel injection pressure. These features allow the C18 to completely control injection timing, duration and pressure.

Electronic Control Module

The ECM responds to operator commands and engine sensor input to optimize engine and machine performance. This advanced engine management software controls and protects the engine at all times against cold starts, high altitude operations and air filter plugging by monitoring:

  • injection timing and pressure
  • engine cooling fan speed
  • ether starting aid
  • hydraulic pumps
NGMR Engine Cooling System

The standard radiator for the tractor is the Next Generation Modular Radiator (NGMR), which features 9 fins per inch rather than 33 fins per inch found on previous models. The increased radiator fin spacing for both the tractor and the scraper reduces clogging in severe applications. Two-piece service doors improve access to clean out debris.

Extended Oil Change Interval

Oil change intervals in both the C18 and C9 engines can be extended to 500 hours with the use of S•O•SSM analysis.

Power Train - Transmission


Electronically controlled Caterpillar planetary powershift transmission with eight forward and one reverse speed. Tractor gears 1 & 2 operate in converter drive for increased torque capability during cut and fill operations. Gears 3-8 operate in direct-drive for drive train efficiency during the haul. All scraper gears operate in converter drive for increased torque capability during the cut and fill.

Final Drives

Outboard-mounted, planetary design final drives reduce torque loads on other power train components. Large-capacity, double-row roller bearings and Caterpillar Duo-Cone® seals deliver exceptional reliability in the toughest applications.

Independent Brake Systems

Expanding-shoe type brakes use a cam-operated design, which is air-applied and spring released. The secondary braking system uses independent front and rear circuits that are automatically applied if the service air pressure drops to 55 psi (380 kPa). Audible and visual action alert indicators inform the operator when the service air pressure drops to 75 psi (518 kPa).


Full hydraulic power steering provides automotive feel with positive, modulated flow control for constant steering response. An optional supplemental steering system is ground-driven and provides hydraulic power for steering if needed.


Cushion Hitch

The electronically actuated cushion hitch incorporates a parallelogram-type linkage for exceptional strength with nitrogen accumulators to deliver a smooth ride for enhanced operator comfort.

  • cushion hitch lock down control for positive cutting edge down pressure when loading or spreading
  • controlled oil flow dampens rebound oscillation
  • leveling valve automatically centers piston in cylinder for all loads
  • steel castings are used extensively to eliminate many welded joints and increase strength
  • double-kingbolt design withstands high external forces and simplifies installation and removal

Operator Station

Multi-Adjustable Seat

The Cat Comfort Cloth Seat offers an adjustable seat and armrests for maximum operator comfort.

  • Swivels and locks in four positions (0º - 10° - 20° - 30º) providing the optimum operating position in the cut or on the haul.
  • Adjustable 4 inches fore/aft and 8 inches vertical height to accommodate various sized operators.
  • Static seat belt is standard. A retractable non-cinching seat belt is available as an option.
Revised Steering Column

Increases legroom a full 3.5 in (89 mm), and reduces knee contact.

Standard Air Conditioning

Standard air conditioning system with relocated louvers enhances airflow in the cab.

Storage And Amenities

Convenient storage location includes space for a lunch box and first aid kit. The cab also has a cup holder as well as an ashtray.


The redesigned hood has sloped corners to maintain visibility while accommodating the low emissions engine. The redesigned hood and front shroud are wider to enclose the air-to-air aftercooler (ATAAC), ether starting aid, and lights. The exhaust is located at the back of the hood for good visibility to the right side.

Instrument Display Panel

Features a new quad-gauge layout showing engine coolant temp, transmission / torque converter oil temp, fuel level, and system air pressure. The 637G tachometer can monitor either front or rear engine speeds. Once the 637G tractor engine has been started, the operator can start the rear engine from inside the cab using a switch on the instrument panel. EMS III can display both front and rear engine information right in the cab.

Engine Speed Lock Controller

Enhances operation during long haul cycles by allowing the operator to maintain a desired engine speed without maintaining pressure on the throttle.

Simplified Transmission Control

Simplifies gear selection (1st, 2nd, Drive and Reverse) and allows operator-defined top gear control. Relocating the gear control to the rear increases operator legroom.

Grab Handle / Hand Rest

The grab handle/hand rest next to joystick controller gives operators a place to rest their hand while on the haul and return roads.

Single Lever Implement Control

Simple and easy to operate, the joystick enhances the productivity of operators of all skill levels. Requires less force to control the critical scraper functions and requires less lever travel. 1) Bowl (forward & back) 2) Ejector (side to side) 3) Apron (thumb rocker switch) 4) Transmission Hold 5) Cushion Hitch 6) Rocker switch (not shown - is on front of joystick)

  • Auger (on/off)
  • Push-Pull (bail up/down)

* Standard open bowl does not have a rocker switch.

Electronic Controls

Simplified System

The electrical system has been redesigned to utilize three electronic control modules (ECM) on the tractor instead of four. The rear-powered scraper now has two ECMs rather than three.

Improved Serviceability

Combined monitoring systems, easy access diagnostics and more durable components make routine maintenance and servicing simple and fast.

Product Link

Product Link is a wireless system that allows the customer to track machine data such as location, service meter hours as well as machine health information. The system can automatically issue alerts when the machine is operated beyond owner-defined time and location limits. Product Link is available as a factory attachment or it may be installed in the field, in that there is a mounting location for the module as well as an antenna on the machine. A wiring breakout is standard, without having to splice into existing wires.

Fuel Economy

Electronic controls yield a fuel savings by optimizing the timing setting for varying conditions. The ADEM A4 controller matches timing to the load on the engine, engine rpm and temperature.

Reduced Exhaust Smoke

The ADEM A4 controller reads electronic sensors to determine the optimum fuel/air ratio. Fuel is precisely controlled during cranking, starting and acceleration to reduce smoke. The Engine Electronics are faster and more efficient than mechanically controlling the governor rack position.

Scraper Bowl

Redesigned Bowl

The redesigned bowl minimizes falling material lodging between the bowl and the draft arm, resulting in premature wear. The modifications also provide better load retention on level ground or traversing down a grade. Bowl capacity has been increased by 3 yd3 (2.3 m3), allowing more material to be moved.

  • Low-profile bowl design offers less resistance to incoming materials.
  • Cellular construction adds strength and dent resistance to bowl sides and floor.
Bulldozer Ejection System

Cat bulldozer ejection system offers constant spreading control with minimal material carry back. A spill guard helps retain material and keep it from spilling over onto the rear of the scraper (standard on tandem engine scrapers, optional on single engine open bowl scrapers).

Cutting Edges

May be adjusted according to job conditions. The stinger (drop down) position provides good penetration and efficient flow of material into the bowl whereas the level cutting edge is used for finish work or very high impact conditions.

Tandem Engine

Two engines ensure the power to handle steep grades, and makes possible all wheel drive to handle soft, slippery underfoot conditions.

Dual Horsepower

On the tandem engine scraper, the rear engine has dual horsepower capability that results in better performance on the haul roads.

Material Application

Well suited to handle a wide variety of material from clay to shot rock.

Push-Pull Arrangement

Push-Pull Attachment

This optional arrangement concentrates the combined horsepower of two machines onto one cutting edge. The push-pull attachment allows two individual machines to act as a self-loading system, typically loading both machines in less than a minute.

Flexible Fleet

This system provides a more balanced, flexible fleet using fewer machines and less investment than comparable self-loading or push-loading systems.

Hydraulically Actuated Bail

The push-pull arrangement uses a hydraulically actuated bail and cushioned plate bolted to the front of the tractor, and a hook that is attached to the rear of the scraper. There is an actuator indicator light on the dash that will turn on when the trigger is engaged to actuate the push-pull bail or auger.

Auger Arrangement


The auger has a wide material appetite ranging from rock to free flowing material such as sand.

Auger Mechanism

The auger lifts material off of the cutting edge and carries it to the top of the load for true self-loading capability. Material is distributed evenly throughout the bowl, resulting in consistent loads.

Material Handling

The auger actions on the material produce several benefits:

  • wide material appetite, ideal for landfills
  • blends the material to help eliminate voids in the bowl for consistent payloads
  • reduces dust and noise during loading
Dual Horsepower

Tractor engine automatically reverts to the higher setting when the auger motor is engaged.

Slip Limiter Switch

Prevents rear wheel spin during loading.

Hydraulic System

Single hydraulic system for entire machine with separate implement pumps/valves simplifies maintenance and improves reliability.

Implement Valve Relocation

The implement valve has been relocated from the tractor to the top of scraper draft tube. The result is fewer hoses and tubes that cross over the gooseneck, and fewer potential leak points. The relocation also improved access to the implement valve for better serviceability.

Electro-hydraulic Controls

The 637G features full electro-hydraulic controls, which simplify serviceability and reduce noise by replacing the cab pilot valves with a single-lever joystick control. The high-efficiency electro-hydraulic pilot oil filter provides cleaner oil for the pilot system.

Full-flow Circuits

The hydraulic system features closed-loop, full-flow hydraulic circuits powered by gear-type and piston-type pumps.


Prevents material spillage and retains fine material far better than an elevating scraper.


Grouped Service Points

Maintenance and service points for the engine are grouped on the right-hand side for easy access. They include the engine air cleaner, engine oil check and fill, fuel filters and priming, coolant level sight glass, window washer bottle, air conditioning dryer cartridge, ether starting aid canister, engine oil filter, fan drive lubrication, and sampling ports for the engine oil and coolant.

  • Spin-on fluid filters for all but the main hydraulic filter
  • Cab wiring harness redesigned and relocated for better serviceability

Customer Support

Product Support

You will find nearly all parts at our dealer parts counter. Cat dealers use a world-wide computer network to find in-stock parts to minimize machine down time. Save money with genuine Cat Reman parts. You receive the same warranty and reliability as new products at substantial cost savings.

Machine Selection

Make detailed comparisons of the machines under consideration before purchase. Cat dealers can estimate component life, preventive maintenance cost, and the true cost of lost production.


Look past initial price. Consider the financing options available as well as day-to-day operating costs. Look at dealer services that can be included in the cost of the machine to yield lower equipment owning and operating costs over the long run.

Customer Support Agreements

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


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

Maintenance Services

Talk to your dealer about the range of available maintenance services. Repair option programs guarantee the cost of repairs up front. Diagnostic programs such as S•O•SSM Analysis and Coolant Sampling and Technical Analysis help avoid unscheduled repairs.


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

Standard Equipment: