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Overview of Twin Disc MG520 Marine Gear
The Twin Disc MG520 Marine Gear is a heavy-duty, precision-engineered marine transmission widely used in commercial and recreational vessels. Built for reliability under extreme marine conditions, this gear provides consistent torque delivery, smooth clutch engagement, and dependable performance in workboats, tugs, ferries, fishing vessels, and other propulsion applications.
Over time, even the most robust equipment experiences wear. Regular maintenance and timely overhauls with quality parts ensure continued reliability. This guide outlines the most recommended replacement parts, rebuild kits, and aftermarket alternatives for the Twin Disc MG520 Marine Gear to help vessel owners, captains, and marine mechanics keep operations running smoothly and avoid costly downtime.
For more technical details, including torque specs, gear ratios, and factory procedures, please refer to the OEM service manual for the MG520-1 Marine Gear.
Parts Catalog for Twin Disc MG520 Marine Transmissions
Rebuilt Twin Disc MG520 Marine Transmissions
Plate Kit For Twin Disc MG520 Marine Transmission
Gasket Kits For Twin Disc MG520 Marine Transmission
Recommended Replacement Parts For The Twin Disc MG520 Marine Gear
To maintain optimal function and avoid unexpected failures, the following parts should be inspected and replaced during routine service intervals or during a full rebuild.
1. Clutch Plates
Clutch plates are the heart of the marine gear’s engagement system. They ensure smooth transitions between forward, neutral, and reverse gear. With prolonged use, clutch plates can wear down, resulting in slippage, harsh shifting, or complete gear disengagement.
Why Replace Clutch Plates:
- Slipping under load or acceleration
- Harsh or delayed engagement
- Routine overhaul recommendations (based on hours or calendar time)
Clutch Plate Types for MG520:
- Friction Plates: Coated with high-friction material to grip mating surfaces.
- Steel Plates: Act as reaction surfaces and help dissipate heat.
Signs of Wear:
- Burnt or glazed surfaces
- Warping or thickness loss
- Presence of metal debris in oil
Pro Tip: Always replace full sets rather than individual plates to ensure even pressure and performance.
2. Seal and Gasket Kits
Seal and gasket kits are essential for ensuring oil-tight performance and avoiding contamination or fluid loss, which can result in catastrophic failure if not caught early.
Components Included in a Typical Kit:
- Input and output shaft seals
- Oil pan gaskets
- Clutch housing gaskets
- O-rings and lip seals
- Pump housing gaskets
Why Replace Seals and Gaskets:
- Aging rubber leads to hardening or cracking
- Leaks at mating surfaces or shaft exits
- Water or contaminants in transmission oil
- Preventative replacement during rebuild
Seal Replacement Tips:
- Use a proper seal puller and press-in tools
- Clean mating surfaces thoroughly
- Use high-temperature, marine-grade sealants if required
3. Bearings and Bushings
Bearings and bushings are critical for the smooth rotation of shafts, load support, and reduction of friction and vibration. When these parts begin to degrade, they can cause internal misalignment and catastrophic failure.
Types Commonly Used in MG520 Marine Gear:
- Tapered roller bearings (input/output shafts)
- Needle bearings
- Bronze bushings (thrust support or secondary gears)
Common Failure Symptoms:
- Gear whine or vibration
- Metal shavings in oil
- Uneven shaft movement or excessive endplay
During Rebuilds:
- Replace all internal bearings and bushings regardless of appearance—microscopic wear matters.
- Always match OEM bearing dimensions and load ratings.
Diesel Pro Power Premium Aftermarket Options For The Twin Disc MG520 Marine Gear
Diesel Pro Power offers high-quality aftermarket rebuild kits and individual components engineered to meet or exceed OEM standards. Whether you are looking for a complete overhaul solution or just key replacements like seals or clutch plates, Diesel Pro’s aftermarket solutions are designed for reliability, cost savings, and immediate availability.
Explore the complete collection here:
👉 Twin Disc MG520 Marine Gear Parts
1. Rebuild Kits for Twin Disc MG520 Marine Gear
Rebuild kits include all the components necessary for a full overhaul. Diesel Pro Power’s kits come with the highest quality parts to ensure long-lasting performance in commercial and industrial marine environments.
What’s Typically Included:
- Full set of clutch plates (steel and friction)
- Complete seal and gasket kit
- Bearings and bushings
- Thrust washers
- Snap rings and retaining clips
Advantages of Diesel Pro Rebuild Kits:
- One-stop solution—no guesswork in sourcing multiple parts
- Expertly matched components for compatibility
- Backed by industry-standard warranties
- Premium-grade materials suitable for commercial marine use
2. Individual Replacement Parts
For minor repairs or preventative maintenance, Diesel Pro also offers individual components for MG520 transmissions, including:
- Input and output shaft seals
- Clutch friction plates
- Steel clutch discs
- Shifter components
- Pump shafts and rotors
- Oil pans and inspection covers
Each part is rigorously tested for fit and function and often available for next-day shipping.
Advantages of High-Quality Aftermarket Components For The Twin Disc MG520 Marine Gear
Why Choose Diesel Pro Power Over OEM
Aftermarket doesn’t mean second-best. In fact, many marine operators worldwide choose Diesel Pro Power for aftermarket parts because of the superior service, immediate availability, and competitive pricing. Here’s why:
1. OEM Matching or Better Materials
Diesel Pro sources and manufactures parts using the same (or superior) materials as OEM suppliers. Friction materials are heat-resistant and engineered for smooth, consistent engagement. Bearings are tested to meet high-load marine operation standards.
2. Cost Savings Without Compromising Quality
OEM parts often carry significant markup. Diesel Pro offers you the ability to get the same performance and longevity without the OEM price tag.
3. Immediate Availability & Fast Shipping
Diesel Pro maintains a full inventory of MG520 parts ready to ship. This reduces downtime for commercial operators and avoids the 2-4 week wait times common with OEM suppliers.
Shipping Perks:
- Same-day shipping on most orders
- Worldwide delivery
- Tracking and expert shipping support
4. Technical Support from Marine Transmission Experts
Choosing the right parts for a rebuild can be tricky. Diesel Pro offers expert technical support to help you select the correct parts, guide you through disassembly questions, and advise on installation best practices.
Support Channels:
- Phone assistance in English and Spanish
- Email and live chat support
- YouTube tutorials and video guides (coming soon)
5. Proven in the Field
Thousands of customers worldwide trust Diesel Pro aftermarket parts to keep their vessels running. From tugboat fleets in the Gulf to commercial fishing trawlers in the Pacific Northwest, these parts have been proven to withstand the harshest marine environments.
Maintenance Recommendations
Keep Your MG520 Marine Gear in Top Condition
Routine Maintenance Tips:
- Change transmission oil at manufacturer-recommended intervals
- Inspect clutch plates every 2,000-3,000 operating hours
- Replace seals at every major service
- Check for unusual vibrations or noise—these often indicate worn bearings
- Always flush the transmission before installing new internal parts
Warning Signs That Signal Service Is Needed:
- Delayed or harsh gear engagement
- Oil leakage around input/output shafts
- Overheating transmission oil
- Metallic particles in drain pan
If you notice any of these symptoms, it may be time for a full rebuild or key part replacements.
Additional Resources
Learn More and Shop Parts
- 🔧 Shop MG520 Marine Transmission Parts
📞 Need Help? Call or chat with Diesel Pro’s marine experts for tailored guidance.
Frequently Asked Questions (FAQ)
How do I know if my MG520 clutch plates are worn out?
Signs include delayed engagement, slippage under load, or burnt oil smell. Inspect the plates visually for warping, thickness loss, or burning.
What comes in a typical MG520 rebuild kit from Diesel Pro?
Our kits include all friction and steel clutch plates, seals, gaskets, bearings, bushings, thrust washers, and snap rings. Every component is selected for performance and durability.
Are your aftermarket parts really as good as OEM?
Yes. Our parts are manufactured to meet or exceed OEM specifications, backed by expert support and proven in real-world marine applications.
Can I install these parts myself or do I need a marine mechanic?
Many experienced boat owners do their own rebuilds. However, we recommend professional installation if you’re unfamiliar with marine transmission systems. Always refer to the OEM manual for torque specs and procedures.
Do you ship internationally?
Yes. Diesel Pro ships parts globally with customs-friendly documentation and fast delivery options.
What if I need just a seal or clutch set, not the full kit?
You can order any individual part directly from our site. All MG520 components are sold individually and in kits.
What tools do I need for a Twin Disc MG520 rebuild?
Typical tools include a bearing puller, hydraulic press, seal drivers, micrometers, snap ring pliers, and standard hand tools. Consult the service manual for specialty tools and torque settings.
What oil should I use after the rebuild?
Use high-quality marine transmission oil per OEM recommendations. Many MG520 operators use SAE 30 or 40 non-detergent oil, depending on ambient temperatures and application load.
Final Thoughts
Why Diesel Pro Power is the Best Source for MG520 Rebuild Parts
The Twin Disc MG520 is a workhorse of a transmission. When the time comes for maintenance or a full rebuild, trust Diesel Pro Power for the right parts, expert support, and fast turnaround. Our rebuild kits save you time, reduce cost, and are trusted worldwide by commercial marine operators and mechanics alike.
Choose Diesel Pro aftermarket parts and rebuild with confidence.
Need help identifying a part? Contact Us Now!
Shop Now: Twin Disc MG520 Marine Gear Parts
Parts Catalog for Twin Disc MG520 Marine Transmissions
Rebuilt Twin Disc MG520 Marine Transmissions
Plate Kit For Twin Disc MG520 Marine Transmission
Gasket Kits For Twin Disc MG520 Marine Transmission
