Selecting, Maintaining, and Troubleshooting Your Gear Reducer

August 3, 2023

A gear reducer, or gearbox, is one of the most significant purchases you will make when assembling an electric motor drive for your application. A reducer that meets your requirements and is well taken care of ensures a long and trouble-free service life and improves the performance, efficiency, and ultimately your application's productivity.

Here are the key things to consider when selecting, maintaining, and troubleshooting your gear reducer.

The Right Gear Reducer Selection

The first and most crucial step in optimizing your gear reducer is making the correct choice in the first place. There are many different types of reducers built for specific input and output performance characteristics that cannot be changed, so you must be careful to select the right one for the job.

Speed and Torque

The purpose of a gear reducer is to provide the optimum output speed and torque to the load at the motor's operating speed, which is typically the motor's base speed, where it is most efficient. Ensure the reducer's reduction ratio is sufficient to provide the torque you need to drive the load and that the output speed is optimal for your requirements. A drive that runs too fast or slow or cannot cope with the demands placed on it will suffer from poor performance and risk damage to the load, the motor, and connected equipment.

Motor Performance

While the necessary calculations involved in selecting a gear reducer are relatively simple, several additional factors are often overlooked, resulting in poor performance or short service life. If your application will experience shock loads or cyclic loads, even for short periods, add a sufficient service factor to the reducer so that it will be able to cope with the increased torque. Also, suppose you require precise control of the speed or position of the load. In that case, it's vital to achieve good inertia matching between the gear reducer and the load, which determines how well the load can be controlled during acceleration and deceleration of the motor.

Level of Efficiency

If reducing your operating costs is important to you, consider which gear system type will work best for your needs. Over a 10-year service life, the purchasing price of an electric motor drive typically only accounts for less than ten percent of the total cost of ownership, and the majority of your expenses will be determined by how efficient your motor and gearbox are. There are many different gear systems available with varying levels of efficiency and performance for various uses. Choosing an efficient one will go a long way toward optimizing your long-term costs, even if it's not the cheapest option.

Maintaining Your Gear Reducer

Once you've selected a gear reducer, there's still plenty to do to keep it maintained and running well over the long term. Here are the most important tips to consider:


Correct lubrication is the single most crucial factor in maintaining your gear reducer and keeping it operating reliably and productively for many years. Improper lubrication causes increased friction, resulting in pitting of the gear surface and a snowball effect that quickly ends in gearbox failure.

Always use the correct lubrication for your reducer as recommended by the manufacturer, which will have the right properties to maximize its performance and service life. Follow recommended procedures for the break-in period when operating a brand-new reducer, which may involve replacing or filtering the oil after a short time to remove any metal filings and particles dislodged from the gear teeth. Periodically check the oil level and quality, and don't over-fill or under-fill it, as both instances can cause a reduction in the lubrication's heat dissipation capability.


The only thing that should enter inside a gearbox is the lubricant. Suppose it is operated in highly polluted or weather-exposed environments. In that case, there is a substantial risk of dust and water particles coming in through faulty seals or exposed bearings, which can wreak havoc on the gears. If necessary, use bearing protection such as rubber seals and shaft slingers to protect the gears from contaminant ingress.

When operating in colder climates, condensation can be an issue, and water inside the gearbox interferes with the lubrication and causes hotspots of friction and damage on gear tooth surfaces. Keep your gear reducer in as sheltered and warm an environment as possible, use desiccant air filters if necessary, and routinely check the oil for signs of water contamination, which typically presents as a milky, cloudy colouring. Immediately replace any contaminated oil.


When storing your gear reducer, keep it in a clean, dry, and climate-controlled environment, with all covers, vents and drains closed and sealed. Maintaining lubrication during storage is vitally important, especially if your reducer is a backup that needs to be ready to go on short notice. Rotate the shaft periodically to distribute the lubrication. Be sure to rotate it by as many turns as it takes to complete a full revolution at the output to ensure that lubrication is spread evenly over the gears.

Troubleshooting Gear Reducer Problems

When your gear reducer is in trouble, you may not have long to find out what the problem is and fix it before permanent damage occurs. Although routine maintenance is your best safeguard, there are additional telltale signs you should be looking out for.

Vibration and Noise

If you notice increased vibration or noise in your gear reducer, it is a strong warning that something is wrong. If possible, rule out the motor by operating it without a load, and check that the load isn't the problem by running the motor and gearbox with no load attached. Noise and vibration are often accompanied by overheating, so check the gearbox surface temperature as well.

If your gear reducer is suffering from excessive vibration, it may be time to have it serviced or replaced to minimize the risk of interruptions to your operations.


Overheating is a common problem when the lubrication in your gear reducer is insufficient or has deteriorated. Check the surface routinely with a temperature gun to track spikes in temperature that indicate increased friction between gears. When this occurs, make a thorough check of the lubrication type and quality. If the lubrication is satisfactory, your reducer may require servicing or replacement.


Your gear reducer is one of the cornerstones of your operation, and making the right choices in selection and maintenance will ensure that it provides you with many years of reliable productivity.

To start putting your gear reducer together, visit our gearbox builder, the simplest and most powerful way to assemble the ideal gear reducer for your specific needs.

Have questions? Get in touch with our experts.

Connect with our expert team via email or phone.



Questions? Contact Us

Related Articles