Industrial Gearbox Overheating: Causes, Checks and Maintenance Tools Malaysia
Meta Description: Learn how to investigate industrial gearbox overheating using thermal cameras, infrared thermometers, vibration meters, tachometers and clamp meters in Malaysia.
Industrial gearboxes naturally generate some heat during operation. However, a gearbox requires investigation when it:
Runs noticeably hotter than before
Develops a localised hot spot
Produces abnormal noise
Shows increasing vibration
Leaks oil
Causes the motor to draw more current
The cause may involve lubrication, bearing condition, gear wear, shaft alignment, equipment load, rotational speed or ventilation.
Common Causes of Gearbox Overheating
The most common causes include:
Low lubricant level
Excessive lubricant
Incorrect lubricant
Contaminated or degraded oil
Excessive equipment load
Bearing deterioration
Gear wear
Shaft misalignment
Incorrect rotational speed
Poor ventilation or high ambient temperature
1. Incorrect Lubricant Level
Both insufficient and excessive oil can make a gearbox run hotter.
Low Oil Level
Insufficient oil reduces lubrication between gears and bearings. This can increase friction, wear, temperature and noise.
Check for:
Oil leakage
Damaged shaft seals
Loose drain plugs
Incorrect filling
Oil-level indicator problems
Excessive Oil Level
Too much oil can cause the rotating gears to churn through the lubricant, creating additional resistance and heat.
Always check the oil level according to the gearbox manufacturer’s procedure.
2. Incorrect or Degraded Lubricant
Gearbox lubricant must suit the:
Gearbox type
Gear design
Operating speed
Load
Working temperature
Manufacturer’s requirement
Using an oil with unsuitable viscosity can cause inadequate protection or excessive resistance.
Inspect the lubricant for:
Discolouration
Burnt smell
Foam
Water contamination
Sediment
Metal particles
Do not mix different lubricants unless their compatibility has been confirmed.
3. Excessive Mechanical Load
A gearbox operating above its intended load generates more heat.
Possible causes include:
Overloaded conveyor
Blocked driven equipment
Seized roller
Product accumulation
Restricted pump
Increased production demand
Incorrect gearbox selection
Use a clamp meter to check whether motor current has increased under the same production condition.
4. Bearing Problems
Gearbox bearings may overheat because of:
Wear
Incorrect lubrication
Contamination
Misalignment
Excessive load
Incorrect installation
Possible warning signs include:
Increasing vibration
Hot bearing areas
Grinding or humming noise
Oil contamination
Shaft movement
Use a vibration meter together with temperature measurements.
5. Gear Wear or Damage
Damaged gears can increase friction and produce:
Whining
Knocking
Grinding
Increasing vibration
Metal particles in oil
Unstable output speed
Localised heat
A basic vibration meter can identify that gearbox condition has changed, but detailed gear-fault diagnosis may require more advanced vibration-analysis equipment.
6. Shaft Misalignment
Misalignment between the motor, gearbox and driven machine can increase stress on bearings, gears, couplings and seals.
Possible signs include:
High axial vibration
Hot input or output bearings
Coupling wear
Oil leakage
Repeated bearing failure
Increasing motor current
Replacing the bearing without correcting alignment may cause the problem to return.
7. Incorrect Gearbox Speed
Higher-than-intended input speed can increase friction, oil churning and bearing load.
Use a tachometer to verify:
Motor RPM
Gearbox input RPM
Gearbox output RPM
The expected output speed depends on the gearbox ratio.
8. Poor Ventilation
A gearbox releases heat through its casing.
Heat dissipation may be reduced by:
Dust-covered surfaces
Enclosed installation
Failed cooling fan
Blocked ventilation
Nearby hot machinery
High room temperature
Clean external surfaces and check airflow according to the approved maintenance procedure.
9. Blocked Gearbox Breather
A blocked breather can increase internal pressure as the gearbox warms.
This may contribute to:
Oil leakage
Seal failure
Moisture retention
Abnormal internal conditions
Inspect the breather during routine maintenance.
How to Check Gearbox Temperature
Infrared Thermometer
An infrared thermometer is suitable for routine checks at known locations.
Recommended points include:
Input-bearing area
Output-bearing area
Gearbox casing
Oil-sump area
Motor casing
The Smart Sensor AR600E is one option for fast, non-contact surface-temperature measurements.
Thermal Imaging Camera
A thermal camera is more suitable when the hot area is unknown.
It allows maintenance teams to compare:
Input and output bearings
Complete gearbox casing
Motor
Coupling
Driven equipment
Nearby heat sources
Record the gearbox load and operating duration with every thermal image.
How to Measure Gearbox Vibration
Take readings at consistent locations:
Gearbox input bearing
Gearbox output bearing
Motor drive-end bearing
Motor non-drive-end bearing
Driven-equipment bearings
Where practical, measure in:
Horizontal direction
Vertical direction
Axial direction
Record RPM and equipment load with the vibration results.
Gearbox Troubleshooting Instruments
What to CheckRecommended InstrumentOverall temperature patternThermal imaging cameraRoutine surface temperatureInfrared thermometerBearing and gearbox vibrationVibration meterInput and output speedTachometerMotor load currentClamp meterAbnormal gearbox noiseSound level meterRoom-temperature changesTemperature data loggerCooling airflowAnemometer
Basic Gearbox Overheating Check
Step 1: Confirm the Temperature
Measure the same gearbox location again.
Step 2: Record Operating Conditions
Note load, running time, input speed and output speed.
Step 3: Check the Lubricant
Verify oil level, type, condition and leakage.
Step 4: Scan with a Thermal Camera
Identify whether the heat is concentrated around a bearing, the oil sump or the complete casing.
Step 5: Measure Vibration
Compare input, output, motor and driven-equipment bearings.
Step 6: Measure Motor Current
Check whether the gearbox or driven machine is creating additional load.
Step 7: Inspect Alignment and Mounting
Check couplings, gearbox feet, motor feet and baseplate bolts.
Step 8: Check Ventilation
Inspect cooling fans, external surfaces and room airflow.
Sudden vs Gradual Overheating
Sudden Temperature Increase
Possible causes include:
Oil loss
Sudden overload
Bearing damage
Blocked driven equipment
Cooling-fan failure
Incorrect maintenance work
Gradual Temperature Increase
Possible causes include:
Lubricant deterioration
Gear wear
Bearing wear
Progressive misalignment
Dust accumulation
Increasing production load
Trend records help maintenance teams distinguish between sudden and gradual changes.
Common Troubleshooting Mistakes
Avoid:
Adding oil without checking the correct level
Mixing incompatible lubricants
Measuring different casing locations each time
Ignoring production load
Ignoring input speed
Replacing bearings without checking alignment
Ignoring a blocked breather
Comparing temperatures after different running periods
Assuming every hot gearbox has damaged gears
Continuing operation after a severe, sudden temperature increase
Gearbox Maintenance Tools Supplier in Malaysia
MTM Precision supplies instruments for investigating gearbox overheating, bearing vibration, incorrect speed, motor overloading and abnormal machinery noise.
Our range includes thermal imaging cameras, Smart Sensor AR600E infrared thermometers, vibration meters, tachometers, clamp meters, sound level meters and temperature data loggers.
Contact MTM Precision
MTM Precision Sdn. Bhd.
Showroom & Service Centre
No. 29-1 & 29-2, Jalan Bandar 18,
Pusat Bandar Puchong,
47160 Puchong, Selangor, Malaysia
🌐 Website: www.mtmpre.com.my
📧 Email: mtmpre@yahoo.com
📱 WhatsApp: +6016-660 7346
31 Aug 2026
