Metal Shavings in Gear Oil on the Mustang MTL25

[MikePhua]

The Mustang MTL25 and Its Mechanical Architecture
The Mustang MTL25 is a compact track loader developed during the mid-2000s by Mustang Manufacturing, a brand under the Manitou Group. Known for its robust undercarriage and high breakout force, the MTL25 was designed for demanding excavation, grading, and material handling tasks. It features a vertical lift path, pilot-operated joystick controls, and a high-flow hydraulic system compatible with a wide range of attachments.
The MTL25 shares its platform with the Takeuchi TL250, as both were built under OEM agreements. This model includes dual travel motors housed within planetary gearboxes, which are lubricated separately from the hydraulic system using gear oil. These planetary drives are critical for torque multiplication and smooth track propulsion.
Terminology Annotation

• Planetary Gearbox: A gear system consisting of a central sun gear, surrounding planet gears, and an outer ring gear, used to transmit high torque in compact spaces.
  
• Travel Motor: A hydraulic motor that powers the movement of the tracks in a compact loader or excavator.
  
• Gear Oil: A high-viscosity lubricant formulated to protect gears under heavy load and shear stress, typically rated SAE 80W-90 or 85W-140.
  
• Metal Shavings: Fine metallic particles generated by gear contact, wear, or break-in processes, often suspended in oil.
  

Finding Metal Shavings in the Gear Oil
During routine maintenance on a 2006 Mustang MTL25, a technician drained the gear oil from both travel motor gearboxes. The passenger-side oil appeared clean, while the driver-side oil contained very fine metal shavings. No large fragments or chunks were present, and the machine continued to track straight with no abnormal noise or vibration.
This discovery often raises concern, but in planetary gear systems, the presence of fine metallic particles is not inherently alarming. These particles are typically the result of normal gear meshing, especially during the early life of the machine or after a rebuild. The key is distinguishing between harmless wear debris and signs of impending failure.
Evaluating the Severity of Metal Debris
To assess whether the shavings indicate a problem:

• Check for grinding, whining, or vibration during travel
  
• Inspect the magnetic drain plug for buildup consistency
  
• Compare oil condition across both gearboxes
  
• Look for discoloration or burnt odor in the oil, which may suggest overheating
  

In this case, the absence of noise and the fine nature of the particles suggest normal wear. Planetary gears operate under high contact pressure, and even with hardened steel components, micro-abrasion occurs over time.
Preventative Maintenance Recommendations
To extend the life of the planetary gearboxes and minimize wear:

• Change gear oil every 200 hours or annually, whichever comes first
  
• Use high-quality gear oil rated for extreme pressure (EP) applications
  
• Install magnetic drain plugs to capture fine particles
  
• Monitor oil color and viscosity during each service
  
• Avoid aggressive turning maneuvers on hard surfaces, which stress the drive system
  

If metal shavings increase in volume or are accompanied by noise, consider disassembling the gearbox for inspection. Look for pitting on gear teeth, bearing wear, or seal degradation.
A Story from the Field
In 2017, a landscaping company in Alberta noticed metal shavings during a winter oil change on their MTL25. Concerned about a potential failure, they consulted a local technician who confirmed the particles were typical for planetary gears. The company began using synthetic gear oil with enhanced anti-wear additives and installed magnetic plugs. Over the next two years, oil samples showed reduced metal content, and the machine continued operating without issue.
Industry Trends and Component Longevity
Modern compact loaders increasingly use sealed planetary drives with synthetic lubricants and integrated sensors. In 2024, Manitou introduced a smart gearbox system with oil condition monitoring and predictive maintenance alerts. While the MTL25 predates these innovations, retrofitting magnetic plugs and adopting oil analysis can bring similar benefits.
Aftermarket suppliers now offer rebuild kits for MTL25 gearboxes, including upgraded bearings and seals. These kits extend service intervals and reduce the risk of catastrophic failure. For machines with over 3,000 hours, proactive inspection of the planetary assembly is advised.
Conclusion
Finding fine metal shavings in the gear oil of a Mustang MTL25 is not necessarily a cause for alarm. Planetary gear systems naturally produce microscopic wear particles under load. As long as the machine operates smoothly and the oil is changed regularly, this condition can be managed without major intervention. By adopting preventative practices and monitoring oil condition, operators can ensure long-term reliability and avoid costly repairs.