Know Your Machine G2 Wheel Shovel
Wheel Shovel Parts
& Functions
Bucket · Hydraulics · Steering · Drivetrain
A plant operator should also understand what each major part does, what it works with and what a change in sound, movement or response may be telling them.
G2 Wheel Shovel / Wheel Loader
A wheel shovel looks fairly straightforward when it is parked: four large tyres, a bucket at the front, a cab near the middle and an engine behind the operator.
Watch one loading a truck, though, and the picture changes.
The engine is producing power. The transmission and axles are getting that power to the wheels. Hydraulic cylinders are lifting and tilting the bucket. Steering cylinders are turning the machine around its centre articulation joint. At the same time, the operator is watching the load, the ground, the instruments and everything moving around the machine.
Learning the names of the parts is therefore only the beginning.
In Kenya’s Category G terminology, the Wheel Shovel is G2. The same type of machine is widely known as a wheel loader on worksites and in technical literature.
This guide concentrates on the machine itself: its bucket and loader arms, hydraulic system, articulated frame, engine, drivetrain, steering, brakes, tyres, cab and supporting systems.
What are the main parts of a wheel shovel?
The main parts of a wheel shovel include the bucket, cutting edge, loader arms, bucket linkage, hydraulic cylinders, front and rear frames, articulation joint, steering cylinders, engine, transmission, drive shafts, differentials, axles, final drives, tyres, brakes, operator’s cab and counterweight.
Hydraulics provide the force needed to lift and tilt the loading equipment. The drivetrain takes engine power towards the wheels.
Instead of memorising these components as a long list, it is easier to follow the machine from the bucket backwards.
From the bucket backwards
Wheel shovel parts and functions at a glance
| Machine area | Main parts | Main job |
|---|---|---|
| Loading end | Bucket, cutting edge, loader arms, linkage | Scoop, carry, lift and dump |
| Hydraulic system | Pump, valves, reservoir, hoses, cylinders | Create and control working movement |
| Chassis and steering | Front frame, rear frame, articulation joint, steering cylinders | Support the machine and allow it to turn |
| Powertrain | Engine, torque converter where fitted, transmission, shafts, axles, final drives | Transfer power towards the wheels |
| Travel and control | Tyres, steering and brakes | Move, turn and stop the machine |
| Operator station | Cab, controls, instruments, protective structure | Control and monitor the machine |
| Rear structure | Engine compartment and counterweight | House major power components and contribute to balance |
The arrangement is not identical on every wheel shovel. Always learn the actual machine you are using and follow its operator manual for machine-specific procedures.
Key external components
Start at the front
Start at the bucket
For a trainee standing beside a wheel shovel for the first time, the bucket is the easiest place to begin.
From there, you can follow almost the entire loading system backwards.
Bucket
The bucket is the machine’s main material-handling attachment.
It enters loose material, carries it and releases it at the dumping point. Depending on the worksite, that may be soil, gravel, sand, aggregate or another loose material.
The bucket repeatedly takes loading and impact forces.
You do not need a structural-engineering calculation to recognise when something has changed. A new crack, distorted section, loose mounting area or movement that was not there before deserves attention.
Cutting edge and teeth
Along the lower front edge of the bucket is the cutting edge.
It meets the material as the bucket enters a pile. Some buckets also use teeth or other replaceable wear components.
Wear is expected here.
Ignoring heavy wear is not.
A badly worn cutting edge or damaged tooth can affect how easily the bucket enters material. Missing, loose or broken components should be noticed during the walk-around.
Carry and control the bucket
Follow the bucket backwards
Behind the bucket is the structure that carries it.
Loader arms
The heavy arms connecting the bucket area to the front frame are the loader arms.
They carry the bucket and allow it to move vertically.
Watch the machine working and you can see the load passing through this structure repeatedly.
Once you know what a healthy loader arm looks like, fresh damage becomes easier to spot: a crack near a weld, distortion, loose mounting points or movement that was not present before.
Bucket linkage
The bucket does more than move up and down. It also has to change angle.
The bucket linkage transfers movement from the tilt cylinder to the bucket. Depending on the design, this may involve connecting links, pivot pins and a rocker or bellcrank arrangement.
When the bucket curls backwards to retain material, the linkage is working.
When the bucket tips forward to dump, the same system carries the movement in the opposite direction.
Pins and bushes
Look closely at the linkage while it moves and you will see several pivot points.
These joints normally use pins and bushes.
The pin forms the pivot shaft. The bushing provides the bearing or wear surface.
Wear does not always announce itself dramatically. The first clue may simply be a knock when the bucket changes direction or a small amount of movement before the attachment responds.
That is why familiarity with the machine matters.
Two different movements
Lift and tilt are two different movements
Beginners often recognise the hydraulic cylinders before they understand which one does what.
There is an easy way to remember them.
Lift cylinders: height
- The lift cylinders act on the loader arms.
- They raise and lower the loader-arm assembly.
- Think: Lift = height
Tilt cylinder: angle
- The tilt cylinder works through the bucket linkage.
- It curls the bucket backwards or tips it forwards.
- Think: Tilt = angle
Once that difference is clear, the front hydraulic system becomes much easier to follow.
Where the lifting force comes from
Where does the lifting force come from?
The bucket, arms and material can be extremely heavy.
Hydraulics provide the force needed to move them.
The complete hydraulic circuit is more complex, but this sequence is enough to understand the basic relationship between the components.
Hydraulic pump
The hydraulic pump produces oil flow for the hydraulic system.
It does not physically lift the bucket by itself. It supplies the flow that can be directed towards the required hydraulic function.
Control valves
When the operator moves a loader control, oil has to be sent towards the right cylinder.
The control valves direct that flow.
From the seat, the operator may only move a lever or joystick. Behind that movement, the hydraulic system is routing oil to make the requested action happen.
Hydraulic cylinders
A hydraulic cylinder converts hydraulic energy into straight-line mechanical movement.
On the loader end, cylinders provide functions such as lifting the arms and tilting the bucket.
Cylinder rods, seals and hose connections are useful inspection areas.
If a previously clean rod becomes coated in fresh oil, something has changed.
Hydraulic hoses and pipes
Oil travels between pumps, valves and actuators through hydraulic hoses and pipes.
Look for obvious abrasion, rubbing, cracking, poor routing or leakage.
Never use your hand to search for a suspected high-pressure hydraulic leak.
High-pressure oil can penetrate the skin. Stop, isolate and report the problem according to the machine and site procedure.
Reservoir and filters
The hydraulic reservoir stores oil used by the hydraulic system.
Filters help control contamination.
Oil specifications, filter servicing and hydraulic repairs should follow the machine manufacturer’s instructions and approved maintenance procedures.
Practical identification
Can you find these parts on the machine?
Identify the components without reading a label
- With the wheel shovel safely parked and under the instructor’s direction, stand where you can clearly see the loader assembly.
- Find the lift cylinders first.
- Now locate the tilt cylinder.
- Follow the bucket linkage visually and work out which movement raises the bucket and which one changes its angle.
- Next, identify the front frame and rear frame.
- Where do they meet?
- That centre connection is the articulation joint.
- Repeat the exercise until you can point to each part without reading a label.
- That kind of identification is far more useful than memorising a list the night before an assessment.
The machine bends in the middle
Why does a wheel shovel bend in the middle?
One of the most important parts of the machine sits between the front and rear sections.
Front and rear frames
A conventional articulated wheel loader has two main chassis sections.
The front frame carries the loader equipment and front axle.
The rear frame normally carries components such as the engine, rear axle and counterweight.
The two frames meet around the articulation area.
Articulation joint
A wheel shovel does not normally steer like an ordinary rigid-frame road vehicle.
Hydraulic steering cylinders change the angle between its front and rear frames.
The sequence is roughly:
Steering input → steering hydraulics → steering cylinders → frames pivot → machine turns
Watch a wheel shovel turn from a safe position and the movement becomes obvious. The machine effectively bends around the centre.
The articulation crush zone
That movement creates a serious hazard.
The distance between parts of the front and rear frames changes when the machine steers.
Nobody should stand inside the articulation area merely because the machine appears stationary.
Approved maintenance may require an articulation lock or another isolation procedure. Those procedures belong to properly controlled maintenance work.
For the operator, the important habit is simple:
Know where the articulation zone is and stay clear of it.
Follow uneven ground
Why can the rear axle move?
Look underneath many articulated wheel loaders and you will find another useful mechanical detail.
The rear axle may be able to oscillate relative to the frame.
Imagine one rear tyre climbing over uneven ground.
A completely rigid arrangement would make it harder for all four tyres to follow the surface effectively.
Axle oscillation allows the rear wheels to move with uneven terrain while the centre articulation handles steering.
Different machines use different axle and mounting arrangements, so the principle matters more than memorising one manufacturer’s layout.
Power to the tyres
Follow the engine’s power towards the tyres
Hydraulics move the working equipment.
The drivetrain moves the machine itself.
Some wheel shovels use different drive systems, so treat this as a learning model rather than a universal internal diagram.
Engine
The engine is the main source of machine power.
Its output supports machine travel and other systems, including hydraulics.
The operator’s concern is not dismantling the engine. It is recognising whether the machine sounds, smells, feels and behaves normally.
Unusual smoke, temperature, vibration, noise or warning indications deserve attention.
Torque converter
Many conventional wheel loaders use a torque converter between the engine and transmission.
You do not need to know what is happening inside the converter to operate the loader well.
What matters is understanding where it sits in the power path and that it helps transfer engine power into the drivetrain as operating loads change.
Other machines may use different drive arrangements.
Transmission
The transmission turns engine output into usable machine travel.
Wheel shovels repeatedly change between forward and reverse while loading.
Smooth, familiar response therefore matters.
A delay that appears suddenly, harsh engagement or a new vibration should not simply become “normal” because the machine can still move.
Drive shafts
Drive shafts transfer rotational power towards the axles.
An operator normally sees them during inspection rather than interacting with them directly.
Knowing where they are helps when describing the location of a new vibration or noise.
Differentials
The differential sits within the axle drivetrain.
It transfers drive while allowing wheels on the same axle to rotate appropriately as the machine moves and turns.
Final drives
Near the wheel ends are the final-drive components.
They provide the final stage of power reduction and transfer towards the wheels.
An easy memory cue is:
Differential = distribute
Final drive = reduce and deliver
Contact, stopping and balance
Tyres, brakes and counterweight
Tyres do far more than carry the machine
The tyres support the machine, transmit traction and carry constantly changing loads.
Think about what happens during one loading cycle:
the machine drives into the pile;
reverses;
turns;
travels with material;
stops;
then starts again.
The tyres are involved throughout.
During a walk-around, look for obvious cuts, abnormal deformation, exposed reinforcement or visibly damaged wheel hardware.
Tyre inflation, removal and repair can involve serious hazards and should follow approved procedures.
Service brake and parking brake do different jobs
The service brakes slow and stop a moving machine.
The parking brake holds the stationary machine under the conditions specified by the manufacturer.
Remember:
Service brake = stop
Parking brake = hold
If braking behaviour changes, treat the change seriously.
A heavy wheel shovel is not the machine on which to “see whether the brakes improve after another trip.”
Why is there a counterweight at the rear?
A loaded bucket places considerable load towards the front of the wheel shovel.
The rear counterweight contributes to the machine’s designed balance.
It does not make the machine impossible to overturn.
Machine stability still depends on factors such as load, bucket height, ground condition, travel, turning and operating limits.
Stability must therefore be understood as a whole-machine issue.
Where the systems come together
Inside the wheel shovel cab
The cab is where all the mechanical systems come together for the operator.
Depending on the machine, you may find steering controls, accelerator and brake pedals, transmission controls, loader controls, switches, gauges, warning indicators and electronic displays.
The exact arrangement may differ, but the purpose remains the same: control the machine and monitor its condition.
Inside the cabin
Steering controls
The visible steering control may be a steering wheel or another approved control arrangement.
Behind it, the steering system eventually acts on the cylinders that turn the articulated frames.
Loader controls
Loader controls command movements such as lift, lower, curl and dump.
A familiar machine should respond predictably.
If the same control suddenly produces hesitant, uneven or unusually slow movement, that change is useful information.
Transmission controls
Transmission controls allow the operator to choose direction and, depending on the machine, travel ranges or operating modes.
Never climb into an unfamiliar wheel shovel assuming its controls are identical to the last one you used.
Instruments and warnings
The dashboard tells you what the machine cannot explain in words.
Depending on the design, it may display temperature, fuel, operating hours, transmission information and warning indications.
A good operator learns the normal readings before something goes wrong.
Operator protection
ROPS and FOPS protective structures
The cab may incorporate protective structures designed to provide protection during events such as rollover or falling-object exposure.
These are commonly referred to as ROPS and FOPS.
They are safety structures, not ordinary body panels.
Damage or unauthorised modification should receive proper technical assessment.
Main operator-recognition points
Inside the wheel shovel engine compartment
Open the engine compartment and the machine can suddenly look much more complicated.
There is no need to memorise every hose and wire.
Start with the main operator-recognition points.
Inside the engine compartment
Engine and engine-oil checking point
Know where the machine-specific engine-oil checking point is and how the manufacturer’s procedure says it should be checked.
The goal is recognition and routine inspection, not internal engine repair.
Cooling package
Heavy work creates heat.
The cooling system may include the radiator, fan, coolant reservoir, hoses and other cooling elements.
Debris, leakage and restricted airflow can affect cooling performance.
If the temperature indication moves outside the machine’s familiar working behaviour, pay attention.
Air cleaner
The engine needs clean air.
The air-cleaning system helps keep dust and dirt from entering the engine.
That is especially important on dusty construction and material-handling sites.
Fuel filters and water separator
Depending on the machine, the fuel system may include filters and a water separator.
These help protect the fuel system from contamination.
Know where the visible service points are without dismantling components you are not authorised to service.
Battery
The battery provides electrical energy for starting and other electrical functions.
Look for obvious damage, poor mounting or other abnormal conditions during authorised inspection.
Hydraulic reservoir
The hydraulic reservoir may also be accessible around the rear service area.
Know where the level indication is and how the specific machine requires it to be checked.
Quick distinctions
Don’t confuse these wheel shovel parts
| Parts | Difference | Easy memory |
|---|---|---|
| Lift cylinder vs tilt cylinder | Lift changes loader-arm height; tilt changes bucket angle | Height · Angle |
| Hydraulic hose vs cylinder | Hose carries oil; cylinder creates movement | Carry · Move |
| Front frame vs rear frame | Two chassis sections connected at the articulation joint | Front loads · Rear powers/balances |
| Service brake vs parking brake | Service brake slows/stops; parking brake holds | Stop · Hold |
| Differential vs final drive | Differential distributes drive; final drive provides the last reduction towards the wheel | Distribute · Deliver |
| Pin vs bushing | Pin forms the pivot shaft; bushing forms the wear surface | Pivot · Wear |
| Loader arm vs bucket linkage | Arms raise the bucket; linkage changes bucket angle | Lift · Rotate |
See the whole machine working
Watch one complete loading cycle
The machine makes more sense when the parts stop being separate definitions.
Imagine the wheel shovel approaching a stockpile.
- Power is already flowing
The engine is running and supplying the machine’s systems.
- The drivetrain moves the loader
Transmission, shafts, axles, final drives, wheels and tyres carry the machine towards the material.
- The bucket enters the pile
The cutting edge meets the material.
The bucket and loader structure are now taking loading forces.
- The bucket curls
The hydraulic system directs flow towards the tilt function.
The tilt cylinder and linkage change the bucket angle and help retain material.
- Loader arms rise
The lift cylinders raise the loader-arm assembly.
- The machine reverses
The transmission changes direction and the drivetrain carries the machine away from the pile.
- The loader turns
Steering hydraulics move the steering cylinders.
The front and rear frames pivot around the articulation joint.
- The material travels
The drivetrain keeps the machine moving while the loader structure carries the load.
- The bucket dumps
The tilt system rotates the bucket forwards and releases the material.
What appears to be one simple scoop-and-dump movement is actually the engine, hydraulics, linkage, steering, articulation, drivetrain, axles, tyres and operator controls working together.
That is where the names of the parts begin to make sense.
Observe before you diagnose
What changes should an operator notice?
Operators do not diagnose every fault.
They are, however, often the first people to notice that something has changed.
A slow bucket does not automatically mean the pump has failed.
A new vibration does not automatically mean there is an axle problem.
Several faults can produce similar symptoms.
The useful skill is recognising the change and describing it clearly.
| What you notice | Area worth attention |
|---|---|
| Bucket becomes unusually slow | Hydraulic or loader system |
| Fresh oil appears around a cylinder | Hydraulic system |
| New knock develops around the linkage | Pins, bushes or linkage |
| Steering response changes | Steering or articulation |
| Braking response changes | Brake, tyre or related system |
| New vibration appears while travelling | Tyres, wheels or drivetrain |
| Engine temperature rises abnormally | Engine or cooling system |
| New drivetrain noise develops | Transmission, shaft, axle or final drive |
| Bucket behaves differently while holding position | Loader hydraulic system |
| New warning indicator appears | System identified by the monitoring display |
Build a baseline
Learn what normal feels like
Time around a healthy machine gives an operator something a manual cannot provide on its own: a baseline.
Normal steering has a familiar response.
Normal hydraulics have a familiar speed.
Normal braking has a familiar feel.
A healthy engine has a familiar sound.
Once those things become familiar, small changes begin to stand out.
Know the boundary
Operator knowledge is not mechanic knowledge
Identify, check and recognise
- A plant operator should understand the machine well enough to identify its major parts, explain their basic functions, complete authorised routine checks and recognise unusual behaviour.
Deeper diagnosis and repair
- A qualified mechanic or technician takes over when deeper diagnosis or repair is required.
- Hydraulic-pressure testing, transmission dismantling, internal engine repair, axle rebuilding, cylinder rebuilding, structural repair and complex electrical diagnosis belong with properly trained personnel.
A good operator does not prove mechanical knowledge by taking components apart.
Useful defect reporting
Give the mechanic useful information
“The wheel shovel has a problem.”
“After the machine had worked for about an hour, the bucket started lifting more slowly. I also noticed fresh hydraulic oil around the left lift cylinder.”
The second report tells the technician:
- what changed;
- when it changed;
- which function was affected;
- where the operator noticed something unusual.
Basic mechanics improves communication as much as it improves machine knowledge.
Walk-around revision
A simple G2 revision walk-around
Repeat the walk in both directions
- Start at the bucket.
- Identify the cutting edge.
- Follow the bucket backwards to the linkage.
- Find the tilt cylinder.
- Find the loader arms.
- Locate the lift cylinders.
- Follow the hydraulic hoses safely with your eyes.
- Look towards the front axle and tyres.
- Move towards the centre and identify the articulation joint.
- Find the steering-cylinder area.
- Locate the cab.
- Move towards the rear axle.
- Identify the engine compartment.
- Finish at the counterweight.
- Now repeat the walk in the opposite direction and explain the function of each component without reading your notes.
- Once you can do that comfortably, the wheel shovel stops looking like a collection of unrelated parts.
- It begins to make sense as one machine.
Frequently asked questions
Wheel shovel parts and basic mechanics FAQs
Is a wheel shovel the same as a wheel loader?
For the machine covered here, Wheel Shovel is the G2 terminology used in the Kenyan Category G context. Wheel loader is the more widely used industry name for the same general machine type.
What are the main parts of a wheel shovel?
The main parts include the bucket, loader arms, linkage, hydraulic cylinders, articulated frames, engine, transmission, axles, final drives, tyres, steering system, brakes, cab and counterweight.
What is the difference between the lift cylinder and tilt cylinder?
Lift cylinders raise or lower the loader arms. The tilt cylinder changes the bucket’s angle through the linkage.
What is the articulation joint?
It is the central connection between the front and rear frames. Steering cylinders change the angle between those frames so the machine can turn.
Why does the rear axle oscillate?
On many articulated wheel loaders, rear-axle oscillation helps the rear wheels follow uneven ground. The arrangement varies between machines.
What does the hydraulic pump do?
It produces hydraulic-oil flow. Control valves then direct that flow towards the hydraulic function requested by the operator.
What is the difference between a differential and a final drive?
The differential distributes drive through the axle. The final drive provides the last stage of reduction and power transfer towards the wheel.
Why should a wheel-shovel operator learn basic mechanics?
Because knowing how a healthy machine normally behaves makes it easier to recognise changes early, report defects clearly and avoid treating an abnormal condition as normal.
Institutional / Technical review
Technical review
“Once you understand how the parts work together, the machine starts telling you when something has changed. Good operators learn to notice those changes early.”
Engineer Simon Barongo
Institutional / Technical review
Keep each guide focused
Continue learning about G2
This page is deliberately focused on wheel shovel parts, systems and basic mechanics.
Wheel Shovel / Loader Training in Kenya
For practical operation, requirements, course duration and licensing, continue to the Wheel Shovel / Loader Training in Kenya guide.
Wheel Shovel Operator Career in Kenya
For jobs, employer expectations and career progression, use the Wheel Shovel Operator Career in Kenya guide.
Plant Operator Pre-Start Inspection Checklist
For what to inspect before starting work, use the Plant Operator Pre-Start Inspection Checklist.
Plant Operator Safety Rules in Kenya
For wider worksite hazards and safe operating behaviour, use the Plant Operator Safety Rules in Kenya guide.
Keeping those subjects on separate pages makes each guide more useful and avoids repeating the same material across the site.
From names to judgement
Learn by seeing, then by operating
Reading the names of the components gives you a foundation.
Practical training is where those names begin to make sense.
You see the loader arms carry a real load.
You watch the articulation joint move.
You feel the difference between bucket curl and loader lift.
You begin to recognise the sound and response of a healthy machine.
That is when basic mechanics becomes operator judgement.
Machine: G2 Wheel Shovel / Wheel Loader
Learning focus: Parts, functions and operator-level basic mechanics
Institutional / Technical review: Engineer Simon Barongo
Machine-specific procedures take priority
Technical information note
Wheel-shovel designs vary by manufacturer, model, year and drive system. Component locations, hydraulic arrangements, drivetrain layouts, operating limits and inspection procedures are therefore not identical across all machines.
The operator manual for the specific machine, authorised maintenance instructions and site safety procedures take priority wherever machine-specific requirements apply.