Introduction

Proper storage and preservation of the Twin Disc MG518 Marine Gear is essential for preventing corrosion, contamination, and component degradation during periods of inactivity. Whether the transmission is being stored as a spare unit, removed for seasonal downtime, or awaiting installation, following the correct procedures ensures that it remains in optimal working condition when needed.

This guide provides detailed long-term storage procedures, including:

• Proper long-term storage procedures
• Protective coatings and covers
• Periodic checks during storage
  

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By following these recommendations, vessel owners, marine mechanics, and fleet operators can prevent moisture damage, lubricant breakdown, and mechanical deterioration, ensuring trouble-free operation when reinstalled.

Proper Long-Term Storage Procedures

Storing the Twin Disc MG518 Marine Gear requires preparation and periodic maintenance to prevent damage from humidity, dust, and temperature fluctuations.

1. Preparing the Transmission for Storage

Before storing the MG518 Marine Gear, follow these steps to protect internal and external components:

1. Drain Used Transmission Fluid
   

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   • Old fluid can degrade over time and cause corrosion and sludge buildup.
   • Drain completely and flush with clean transmission oil to remove contaminants.
     

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2. Refill with Fresh Oil
   

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   • Fill the transmission with new, manufacturer-recommended transmission oil.
   • This prevents internal rust formation and keeps moving parts lubricated.
     

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3. Seal Openings and Ports
   

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   • Plug all input/output shafts, oil cooler ports, and vent openings to prevent:
     • Moisture infiltration.
     • Dust accumulation.
     • Insect or rodent entry.
       

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4. Apply a Rust Inhibitor to Internal Components
   

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   • Coat gears, shafts, and bearings with a corrosion inhibitor or fogging oil.
   • This creates a protective barrier against rust and oxidation.
     

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2. Selecting an Appropriate Storage Location

Choosing the right storage environment is critical to prevent degradation of the marine gear.

Recommended Storage Conditions:

Avoid:

• Storing near corrosive chemicals (e.g., bleach, acids, or saltwater).
• Placing directly on concrete floors, which can trap moisture and cause rust.
• Stacking heavy items on top of the unit.
  

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3. Positioning the Transmission for Storage

• Store the transmission in its normal operating position (horizontal).
• If placed on a pallet or rack, ensure it is secure and stable.
• Use shock-absorbing pads to prevent vibrations from affecting seals and gaskets.
  

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Protective Coatings and Covers

During long-term storage, protective coatings and covers act as an extra barrier against moisture, dust, and physical damage.

1. Protective Coatings for External Components

To protect exterior surfaces, apply anti-corrosion coatings to:

• Bare metal areas (exposed shafts, flanges, and mounting brackets).
• Bolt heads and fasteners to prevent rust.
• Painted surfaces to prevent chipping and oxidation.
  

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Recommended Protective Coatings:

2. Wrapping and Covering the Transmission

• Use breathable covers to prevent condensation buildup.
• Wrap in oil-resistant plastic sheeting or a marine-grade tarp.
• Avoid using non-breathable plastic alone, as it can trap moisture and promote corrosion.
  

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3. Desiccant Packs for Moisture Control

To reduce humidity inside the storage wrap, place desiccant packs near:

• Oil ports.
• Ventilation openings.
• Inside sealed storage crates.
  

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Change desiccant packs every 6 months or when they become saturated.

Periodic Checks During Storage

Even when properly stored, periodic inspections help detect potential issues before they become serious.

1. Routine Storage Inspections

2. Steps for Periodic Shaft Rotation

To prevent bearing brinelling and seal deformation, rotate the input and output shafts manually:

1. Remove protective covers and seals.
2. Turn the shaft by hand several times in both directions.
3. If resistance is felt, apply light oil to moving parts and rotate again.
4. Re-seal and cover the transmission after completing the rotation.
   

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3. Inspect for External Contaminants

Check for:

• Signs of rodents or insects (nests or chewed wires).
• Dust accumulation, which can absorb moisture.
• Corrosion or pitting on any exposed metal.
  

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4. Maintaining the Transmission Fluid During Storage

• If stored for less than 12 months, no fluid change is needed.
• If stored for over a year, replace the transmission fluid before putting the unit back into operation.
  

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Recommissioning the Twin Disc MG518 After Storage

Before reinstalling and using the Twin Disc MG518 Marine Gear, follow these steps to ensure it is in proper working order:

1. Thorough Visual Inspection

• Look for cracks, leaks, or rust formation.
• Ensure all seals, gaskets, and bolts are intact.
• Remove any old protective coatings.
  

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2. Drain and Replace Storage Fluid

• Remove the oil used for storage protection.
• Flush the transmission with clean ATF or hydraulic oil.
• Refill with fresh transmission fluid of the correct grade.
  

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3. Rotate Shafts Before Startup

• Manually rotate the input and output shafts to distribute fresh lubricant.
• If stiffness is detected, inspect bearings and seals for tight spots.
  

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4. Test Electrical and Hydraulic Systems

• Check the gear control system for proper engagement.
• Ensure that all sensor connections are secure.
  

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5. Perform a Dry Test Run

• Start the engine at idle speed.
• Shift between neutral, forward, and reverse gears.
• Observe hydraulic pressure and fluid circulation.
• Listen for abnormal noises or vibrations.
  

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Conclusion

Proper storage and preservation of the Twin Disc MG518 Marine Gear ensures that the transmission remains in top condition during extended periods of inactivity. This guide has outlined:

• Long-term storage procedures, including proper fluid management.
• Protective coatings and covers to safeguard components.
• Periodic inspections and preventive maintenance to prevent degradation.
  

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By following these best practices, marine operators can prevent corrosion, maintain lubrication integrity, and ensure quick recommissioning when the transmission is needed again.

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