Gearbox Repair: Bearing Fatigue, Brinelling, Spalling & Fretting

Bearings are critical in supporting the rotating components within a gearbox, which include the gears themselves, shafts, and other mechanical elements. By reducing friction and enabling smooth rotational movement, bearings prevent excessive wear and tear, reduce energy losses, and ensure power transmission with minimal resistance. Still, we understand all bearings have the potential to meet their limits. 

While it’s rare, having a technician you can turn to if a Falk gearbox needs replacement bearings ensures your machines function at peak performance. That’s why identifying common bearing issues like the ones below has become essential to the success of any industrial job. 

4 Examples of Gearbox Bearing Issues

Setbacks may happen if a gearbox isn’t properly maintained or if the manufacturer’s maintenance guidelines aren’t followed. Unfortunately, unexpected shutdowns cost industrial manufacturing businesses nearly $50 billion yearly.

There’s potential to mitigate financial losses through routine maintenance, proper storage, and other upkeep methods. Knowing the difference between bearing fatigue, brinelling, spalling, and fretting is also necessary. 

Mitigate financial losses through routine Falk gearbox maintenance, proper storage, and other upkeep methods.

Bearing Fatigue

The bearings of a gearbox may fatigue in instances of excessive loading, repeated stress cycles, intense vibrations, or if they meet their endurance limit. In those instances, wear becomes apparent and can be identified by: 

  • Cracking in the casing or raceway 
  • Flaking on the case surface
  • Build-up of dry lubricant or rust
  • Missing roller balls

In some cases, bearing fatigue includes sub-surface and surface wear that isn’t easy to spot and requires a professional repair and renewal specialist.  


Every bearing has the potential to reach its limits under rigorous applications in challenging environments that may lead to brinelling. If you’re unfamiliar with that term, brinelling happens when a part is under intense load pressure, resulting in indentations or permanent damage. Here’s how to identify if a gearbox shows signs of brinelling: 

  • Assess the raceway or casing for dents or scratches
  • Test the ball bearings and ensure they run without catching
  • Check for exposed lubricant
  • Examine for flaking materials

It’s rare for a Falk gearbox to be the root cause of brinelling. Instead, damages usually surface from an improperly installed part or an element driving pressure to the bearings. The easiest way to diagnose the problem is by knowing the difference between true and false brinelling. 

  • True Brinelling: Caused by excessive load-bearing, dropping, strong vibrations, or other mishandling. Signs of true brinelling include consistently spaced dents throughout the bearing and sudden mechanical vibrations. 
  • False Brinelling: Caused by repeated drops or vibrations often from poor transport or storage. Signs of false brinelling include dents, signs of wear along the raceway, and noisiness. 


Spalling happens when there’s stress applied to the bearings from extreme pressure, overloading a gear reducer, or sudden environmental changes. While Falk gearbox spalling is rare, it may surface in the following ways: 

  • Broken surface material from gear teeth 
  • Large pits localized on the tooth surface
  • Chipping or other superficial damages

Similarly, case crushing is a form of spalling that causes ruts or wide divots along the gearing teeth. They often appear suddenly below the casing and run upright, weakening the bearing. 


Fretting happens when a bearing creates friction with another surface and slowly removes the material it touches through tension, slippage, or contact pressure. Evidence of fretting include: 

  • Signs of pitting or flakes
  • Superficial material damage 
  • Worn out teeth
  • Evidence of corrosion

The easiest way to prevent fretting is by keeping Falk gearing lubricated and following the manufacturer’s directions. It’s also essential to ensure your Falk gearing isn’t making contact with other surfaces that cause bearing wear. 

NW Industrial, LLC has the largest Falk gearbox inventory in the nation.

NW Industrial Sales LLC: Professional Falk Repair Servicers 

You can replace the bearings or partner with a professional Falk repair technician if you encounter the above situations. Doing so will mitigate the long-term results of wear and tear that will extend the life of any Falk gearbox. 

If you decide to go it alone and need a specific part, our inventory includes a warehouse of Falk gearing and rare or obsolete components. In contrast, we’re eager to meet you if you wish to partner with an expert Falk repair servicer

Contact us today to learn how having the right Falk distributor of new and used parts can keep your business moving. 

2023-08-16T12:58:06+00:00September 19th, 2023|
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