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Rebuilt MG502 Transmissions Available for Immediate Purchase
When reliability and performance matter most, the Twin Disc MG502 rebuilt marine transmission is the solution trusted by marine professionals worldwide. Our rebuilt MG502 transmissions are now available for immediate sale, providing you with a dependable, cost-effective option that minimizes downtime and maximizes vessel performance. These units are expertly rebuilt to original manufacturer specifications by skilled technicians, ensuring that each transmission delivers optimal durability, smooth operation, and long-lasting reliability.
Whether you operate a commercial workboat, a fishing vessel, a high-speed patrol boat, or a recreational craft, the MG502 is engineered to meet your specific performance needs. Each rebuilt transmission is thoroughly tested for quality and functionality, offering a solution you can trust in even the most demanding marine environments.
Our MG502 transmissions are available in a range of gear ratios, providing flexibility to match your vessel’s engine characteristics and operational profile. By selecting the ideal gear ratio for your vessel, you ensure efficient power transfer, fuel economy, and reliable propulsion under varying load conditions. These rebuilt units not only deliver excellent performance but also contribute to environmental sustainability by extending the lifespan of high-quality components and reducing waste.
Available Gear Ratios for Sale
Twin Disc MG502 – 1.54:1 Ratio (For Sale)
This ratio is designed for vessels that require rapid acceleration and high cruising speeds.
- Ideal For: High-speed vessels such as patrol boats, racing craft, and water taxis.
- Engine Match: High-RPM, lower torque engines that demand quick power delivery and agility.
- Performance: Pleasure craft applications up to 149 kW (200 hp) and continuous duty up to 103 kW (138 hp).
- Benefits: Enhanced responsiveness, fuel-efficient operation at higher speeds, and superior maneuverability for vessels that operate in dynamic or high-traffic environments.
Twin Disc MG502 – 2.00:1 Ratio (For Sale)
A versatile option that balances speed and torque, making it suitable for a broad range of marine applications.
- Ideal For: Fishing boats, workboats, mid-sized cruisers, dive boats, and mixed-use vessels.
- Engine Match: Engines with moderate RPM and torque profiles that benefit from a well-rounded balance of power and efficiency.
- Performance: Pleasure craft up to 129 kW (173 hp) and continuous duty up to 88 kW (118 hp).
- Benefits: Reliable power delivery for commercial and recreational vessels, offering excellent fuel economy, smooth handling, and consistent performance in variable conditions.
Twin Disc MG502 – 2.47:1 Ratio (For Sale)
Engineered for vessels that demand high torque and pulling power, this ratio excels in heavy-duty operations.
- Ideal For: Tugboats, trawlers, heavy-duty commercial vessels, ferries, and offshore service boats.
- Engine Match: Low-RPM, high torque engines that require robust, continuous power for demanding operations.
- Performance: Pleasure craft applications up to 103 kW (138 hp) and continuous duty up to 66 kW (89 hp).
- Benefits: Exceptional towing and hauling capacity, reliable performance in challenging marine environments, and durability under high-load conditions.
Each of these rebuilt gear ratios is in stock and available for immediate sale, ensuring you can choose the ideal configuration for your vessel’s specific operational needs. Whether you’re upgrading for better performance, replacing an existing transmission, or preparing for new marine projects, the Twin Disc MG502 rebuilt transmission offers an unmatched combination of reliability, performance, and flexibility. Plus, with gear ratios designed to cover a spectrum of marine applications, you can be confident that your propulsion system will be tailored for maximum efficiency and longevity.
Important Notice: Torsional Vibration
It’s essential to consider torsional vibration when integrating the Twin Disc MG502 transmission with your engine. Torsional vibration, caused by dynamic twisting forces, can lead to misalignment, reduced component life, and operational issues.
- A thorough torsional analysis should be performed during planning or installation to ensure compatibility.
- Ignoring this step may result in drivetrain stress, damage, or costly repairs.
- Consult with a torsional vibration specialist or engine manufacturer for guidance.
- Twin Disc provides best practices for managing torsional vibration and ensuring long-term reliability.
Why Choose a Twin Disc MG502 Rebuilt Transmission for Sale?
When it comes to ensuring the reliability, performance, and cost-effectiveness of your vessel’s propulsion system, the Twin Disc MG502 rebuilt transmission is a standout choice. Here’s why:
- Expertly Rebuilt to OEM Specifications: Each MG502 unit is meticulously disassembled, cleaned, inspected, and reassembled using OEM parts and standards. This process restores the transmission to like-new condition, ensuring dependable performance under even the most demanding marine conditions. Critical components such as clutches, gears, bearings, and seals are either precision-machined or replaced, resulting in a transmission that performs as reliably as a factory-new unit.
- Multiple Ratios Available: With gear ratios of 1.54:1, 2.00:1, and 2.47:1 available, operators can select the configuration that perfectly matches their engine’s power characteristics and the vessel’s operational profile. This flexibility ensures efficient power transfer, optimal fuel economy, and smooth propulsion tailored to a wide range of marine applications.
- Ready to Ship – In Stock: Downtime can be costly in marine operations. That’s why our rebuilt MG502 transmissions are stocked and ready for immediate shipment. Whether replacing a failed unit or planning an upgrade, you can minimize downtime and keep your vessel operational with a transmission that’s rebuilt, tested, and ready to install.
- High-Torque, Marine-Ready: Designed for continuous operation under heavy loads, the MG502 is built to withstand the rigorous demands of marine environments. Its robust construction and precision engineering provide high torque transfer capacity, ensuring smooth operation even in harsh or high-demand conditions.
- Environmental Sustainability: Choosing a rebuilt transmission is not just cost-effective—it’s environmentally responsible. By extending the service life of durable components and reducing waste, the MG502 rebuild process contributes to sustainable practices in the marine industry. This aligns with industry efforts to lower environmental impact without sacrificing performance or reliability.
Expanded Specifications and Technical Details
Model:
Twin Disc MG502 and MG502-1
Weight:
Approx. 70 kg (155 lbs) – making it manageable for installation in a range of marine vessels while offering robust performance capabilities.
Oil Capacity:
3.5 U.S. pints (1.7 liters) – sufficient for maintaining proper lubrication and cooling during operation.
Operating Pressure:
300–350 PSI – ensures effective hydraulic clutch operation and smooth gear transitions.
Recommended Oil:
SAE 40 engine oil – providing optimal viscosity and thermal stability for marine applications.
Speed Range:
600–4000 RPM – accommodating a wide range of engine outputs and vessel types, from high-speed craft to heavy-duty workboats.
Design:
10° down angle – simplifies alignment and installation in vessels with limited space or unique engine room layouts, while improving shaft alignment to minimize vibration and wear.
Key Components Included:
Selector valve, pilot housing flange, oil pump, oil level gauge, output flange – each component is inspected or replaced during the rebuild to ensure optimal function and longevity.
Note: Torsional isolator sold separately, ensuring compatibility with specific vessel and engine configurations.
Performance Ratings
| Model | Ratio | Pleasure Craft (kW/hp) | Intermediate Duty (kW/hp) | Continuous Duty (kW/hp) | Max Input Speed |
| MG502-1 | 1.54:1 | 149/200 | 123/165 | 103/138 | 2900 RPM |
| MG502-1 | 2.00:1 | 129/173 | 110/150 | 88/118 | 2900 RPM |
| MG502-1 | 2.47:1 | 103/138 | 88/118 | 66/89 | 2900 RPM |
These performance ratings underscore the versatility and adaptability of the MG502 across various marine applications. Whether your vessel operates under light loads with intermittent high power, extended medium-duty cycles, or continuous heavy-duty conditions, the MG502 rebuilt transmission is designed to meet the challenge with durability and reliability.
Engine Compatibility for the Twin Disc MG502 Rebuilt Marine Transmission
A key advantage of the Twin Disc MG502 rebuilt marine transmission is its versatility and compatibility with a range of trusted and widely used diesel engines. Designed to deliver dependable performance across various marine applications, the MG502’s adaptability is demonstrated by its proven compatibility with engines from major manufacturers, including Detroit Diesel, Cummins, and Caterpillar. Let’s explore these engines in detail, including their specifications, typical applications, and how they pair with the MG502 for optimal performance.
Detroit Diesel Compatibility
3-53
The Detroit Diesel 3-53 is a compact, lightweight, and reliable three-cylinder two-stroke diesel engine. Featuring a displacement of 159 cubic inches (2.6 liters), this engine is known for its durability and ease of maintenance. Producing approximately 85 horsepower at 2,800 RPM, the 3-53 is ideal for smaller vessels requiring dependable power in a compact form factor.
Applications:
- Small fishing boats
- Patrol boats
- Recreational vessels
- Auxiliary marine power systems
MG502 Pairing: The 3-53’s high-revving, moderate-torque output pairs well with the 1.54:1 gear ratio of the MG502 for applications requiring swift acceleration and responsive handling.
4-53
The four-cylinder version of the 53 series, the Detroit Diesel 4-53, increases displacement to 212 cubic inches (3.5 liters) and horsepower to approximately 140 hp at 2,800 RPM. Renowned for its rugged construction and parts interchangeability, the 4-53 is a favorite for workboats and utility vessels.
Applications:
- Commercial fishing vessels
- Utility boats
- Service vessels
MG502 Pairing: A versatile choice, the 4-53 matches well with both the 2.00:1 and 1.54:1 ratios, depending on the vessel’s desired balance of torque and speed.
6V53
The Detroit Diesel 6V53 is a six-cylinder, V-block engine delivering between 190 and 300 hp depending on configuration. With a displacement of 318 cubic inches (5.2 liters), it provides robust power and high torque at lower RPMs. Its compact design allows installation in tight engine rooms, making it a popular choice for a variety of marine applications.
Applications:
- Patrol boats
- Mid-sized commercial vessels
- High-performance fishing boats
MG502 Pairing: Ideal for pairing with the 2.00:1 ratio, delivering a balanced mix of torque and speed for vessels operating in variable conditions.
2-71
The Detroit Diesel 2-71 is a compact two-cylinder engine with a displacement of 142 cubic inches (2.3 liters). Offering power outputs around 40–60 hp, the 2-71 is typically used in auxiliary systems or small utility boats.
Applications:
- Auxiliary power units
- Small workboats
- Harbor launches
MG502 Pairing: Best matched with the 2.47:1 ratio, maximizing torque for vessels operating at lower speeds or requiring high pulling power.
3-71
The three-cylinder 3-71 increases displacement to 213 cubic inches (3.5 liters) and offers power ratings between 90–120 hp. Its simplicity, reliability, and longevity make it a popular choice for small commercial and fishing vessels.
Applications:
- Small fishing boats
- Harbor workboats
- Pilot launches
MG502 Pairing: A flexible engine that can be paired with either the 1.54:1 or 2.00:1 ratio, depending on the desired vessel performance characteristics.
4-71
Completing the Detroit Diesel 71 series, the 4-71 is a four-cylinder engine with a displacement of 284 cubic inches (4.7 liters). With power outputs ranging from 140–160 hp, it’s a proven workhorse in the marine industry, known for durability and ease of maintenance.
Applications:
- Trawlers
- Small tugboats
- Workboats
MG502 Pairing: Often paired with the 2.00:1 or 2.47:1 ratio, delivering robust pulling power and reliable performance under continuous load.
Cummins Compatibility
4B and 4BT
The Cummins 4B (naturally aspirated) and 4BT (turbocharged) are four-cylinder engines from the renowned B-series family. With a displacement of 3.9 liters, the 4B delivers approximately 75–100 hp, while the 4BT provides 105–130 hp, depending on tuning. These engines are celebrated for their fuel efficiency, simplicity, and reliability, especially in commercial marine settings.
Applications:
- Small workboats
- Fishing vessels
- Pilot boats
MG502 Pairing: The 1.54:1 or 2.00:1 ratio provides the ideal balance of speed and torque, maximizing the 4B/4BT’s fuel-efficient performance.
6B and 6BT
Expanding the B-series line, the 6B and 6BT are six-cylinder engines with a displacement of 5.9 liters. The naturally aspirated 6B typically produces around 135 hp, while the turbocharged 6BT can exceed 180 hp, offering a robust solution for larger vessels requiring higher torque and sustained power delivery.
Applications:
- Mid-sized fishing vessels
- Patrol boats
- Light-duty tugs
MG502 Pairing: These engines pair well with the 2.00:1 or 2.47:1 ratio, ensuring ample torque for demanding marine operations while maintaining fuel economy.
Caterpillar Compatibility
3054
The Caterpillar 3054 is a four-cylinder diesel engine with a displacement of 4.4 liters. Delivering power outputs between 80–130 hp, it’s a compact, high-torque engine commonly found in commercial and industrial marine applications.
Applications:
- Fishing boats
- Utility vessels
- Service boats
MG502 Pairing: Ideal for pairing with the 2.00:1 ratio, balancing torque and speed for vessels operating in diverse conditions.
3056
With six cylinders and a displacement of 6.6 liters, the Caterpillar 3056 produces between 130–200 hp, offering a robust solution for larger commercial vessels. Known for its durability, this engine delivers high torque at low RPMs, enhancing operational efficiency in challenging environments.
Applications:
- Trawlers
- Tugboats
- Workboats
MG502 Pairing: Best matched with the 2.47:1 ratio, maximizing pulling power and ensuring reliable performance under heavy loads.
Construction Features
- Carburized, Hardened, Ground Gears for quiet and durable operation.
- Jig-Bore Accuracy for precise alignment.
- Heat Exchanger Compatibility for high-demand cooling.
- Flexible Installation with multiple coupling options.
Real-World Applications
The rebuilt MG502 units are trusted in:
- Commercial fishing boats
- Recreational yachts
- Patrol and service vessels
- Tugboats and heavy-duty workboats
Conclusion – Ready to Meet Your Needs
The Twin Disc MG502 rebuilt marine transmission, available in 1.54:1, 2.00:1, and 2.47:1 ratios, is designed to deliver reliable, high-performance operation for a wide range of marine vessels. Backed by a thorough rebuild process and available for immediate sale, the MG502 is your assurance of dependable power and long-term reliability.
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