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Twin Disc MG5114A Marine Transmission Parts

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Parts for Twin Disc MG5114A

Upgrade your boat's performance with premium-grade twin disc MG 5114A marine transmission parts and gear from Diesel Pro Power. Durable, dependable, and designed for performance, our MG-5114A Twin Disc Transmission parts collection will deliver the reliable functionality you need for a successful replacement or upgrade application. From oil gauges and coolers to gasket sets, plates, seals, and so much more, shop our entire selection of twin disc MG5114A marine transmission parts and accessories below—as well as many other Twin Disc Transmission parts.

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Marine Transmission Specifications & Applications of the Twin Disc MG5114A

Overview of the Twin Disc MG5114A Marine Transmission

The Twin Disc MG5114A is a dependable marine transmission designed for mid-range horsepower diesel engines used in workboats, patrol vessels, fishing craft, and passenger ferries. This transmission is an enhanced version of the MG5114, featuring refined gear ratios, increased torque handling, and additional compatibility with modern marine engine configurations.

With a rugged cast-iron case, hydraulically actuated clutch, and internal oil-cooling system, the MG5114A is built to endure long operating hours, frequent shifts, and challenging marine environments. It is commonly chosen for both new-build installations and repower projects where space constraints and reliable operation are key factors.

Key Specifications of the Twin Disc MG5114A

  • Type: Marine transmission with hydraulic multi-disc clutch

  • Horsepower Rating (Approximate):

    • Continuous Duty: Up to 500 HP @ 1800 RPM

    • Intermittent Duty: Up to 600 HP @ 2300 RPM

  • Maximum Input Speed: 2500 RPM

  • Reduction Ratios Available:

    • 1.51:1

    • 1.93:1

    • 2.48:1

    • 2.96:1

    • 3.52:1

  • Input Housing: SAE No. 1 or SAE No. 2

  • Flywheel Compatibility: 14", 11.5"

  • Clutch Type: Hydraulically actuated, oil-cooled

  • Cooling System: Oil-to-water heat exchanger (standard)

  • Lubrication System: Pressure-fed internal oil pump

  • Oil Capacity: Approximately 10–12 quarts

  • Dry Weight: 550–650 lbs (depending on configuration)

  • Mounting Options: Straight or 8° down-angle

  • Rotation Compatibility: Bi-directional input (left-hand or right-hand engines)

  • Optional Features:

    • Hydraulic or mechanical PTO

    • Trolling valve

    • Electronic shift integration

Common Marine Applications for the MG5114A

The MG5114A is engineered for medium-duty marine operations that require a combination of endurance, power, and compact design. It is commonly installed in:

  • Government and Patrol Boats: Fast-shifting response and reliable control under tactical conditions

  • Passenger Ferries: Smooth and quiet gear transitions to enhance passenger experience

  • Light Commercial Fishing Vessels: Capable of sustaining long run times under varying loads

  • Charter and Tour Vessels: Supports consistent daily usage with minimal maintenance needs

  • Harbor Utility Craft and Crew Boats: Reliable under frequent shifting, docking, and maneuvering cycles

Most Common Engine Models Paired with the Twin Disc MG5114A

The MG5114A is typically paired with mid-horsepower diesel engines from leading manufacturers. Its bi-directional input and adaptable SAE housing make it suitable for a range of powerplants:

Cummins Marine Engines

  • Cummins QSB 6.7

  • Cummins ISC 8.3
    Popular in crew and utility boats, these engines pair well with MG5114A’s reliable clutch and cooling systems.

Caterpillar Marine Engines

  • Caterpillar 3126

  • Caterpillar C9 (light-duty ratings)
    These Caterpillar engines offer strong torque-to-weight ratios ideal for vessels using the MG5114A.

John Deere Marine Engines

  • John Deere 6090SFM85

  • John Deere 6135SFM85
    Used in ferries and workboats, John Deere engines are a reliable match for this transmission model.

Detroit Diesel Marine Engines

  • Detroit Diesel 6V92

  • Detroit Diesel 8V92 (medium ratings)
    Often used in refits or vessel upgrades, these legacy engines pair well with the MG5114A in compatible layouts.

Advantages of the Twin Disc MG5114A

  • Enhanced Durability: Reinforced internal gearing and clutch packs built for mid-duty commercial use

  • Bi-Directional Input Compatibility: Allows flexibility in engine rotation direction for easier repower planning

  • Improved Oil Cooling and Pressure Lubrication: Keeps the transmission running cooler and smoother under load

  • Optional PTO Integration: Supports hydraulic systems, pumps, and deck equipment

  • Compact with Flexible Output Options: Straight and down-angle versions available for tight engine compartments

Ideal Use Cases for the MG5114A

Vessel Type

MG5114A Suitability

Notes

Crew and Utility Boats

Excellent

Reliable for high shift frequency and long run times

Passenger Ferries and Tour Boats

Excellent

Smooth gear transitions and quiet operation

Law Enforcement / Patrol Vessels

Excellent

Quick engagement and bi-directional capability

Light Commercial Fishing Vessels

Excellent

Designed for all-day power and cooling support

Larger Tugboats / OSVs

Not Recommended

Use MG514B, MG520, or MG521 for heavier load requirements

Additional Resources

Practical Guide To Servicing Your Twin Disc MG5114A

Introduction

  • Overview of the Twin Disc MG5114A Marine Transmission

  • Common applications (tugboats, fishing vessels, crew boats, etc.)

  • Importance of proper servicing and preventive maintenance

  • Disclaimers: For torque specs, tolerances, and detailed rebuild procedures, refer to the OEM service manual

Understanding the MG5114A Marine Gear

Key Specifications For Twin Disc MG5114A Marine Gear

  • Rated horsepower and torque capacity

  • Input speed and reduction ratios

  • Weight and dimensions

  • Mounting configurations and rotation

Component Overview For Twin Disc MG5114A Marine Gear

  • Input shaft and damper coupling

  • Clutch assemblies (forward/reverse)

  • Gear train (helical gear arrangement)

  • Output shaft and companion flange

  • Hydraulic system and oil pump

  • Control valve and actuators

Safety Guidelines For Twin Disc MG5114A Marine Gear

Personal Protective Equipment (PPE)

  • Gloves, goggles, steel-toe boots

  • Inspection and fit guidelines

Safe Handling and Installation Practices

  • Lifting the transmission

  • Alignment with engine flywheel housing

  • Proper bolt torque procedure (general)

Hazard Identification and Mitigation

  • Hydraulic pressure

  • Oil spillage and hot surfaces

  • Pinch and crush points

Routine Maintenance Schedule For Twin Disc MG5114A Marine Gear

Daily Checks

  • Oil level and clarity

  • Unusual vibrations or noise

  • External leaks and loose connections

Weekly Maintenance

  • Oil temperature monitoring

  • Pressure readings (if applicable)

  • Cleanliness of the housing

Monthly Maintenance

  • Drain plug check

  • Vent filter inspection

  • Mounting bolts torque check

Annual or Hour-Based Intervals

  • Full oil change intervals

  • Oil filter change

  • Gear backlash and wear pattern inspection

Oil and Filter Service For Twin Disc MG5114A Marine Gear

Recommended Lubricants and Fluid Specs

  • Oil grade (SAE 30, SAE 40)

  • Brand-neutral advice

  • Operating temperature compatibility

Oil Change Procedure

  • Draining old oil

  • Replacing the oil filter

  • Filling procedure and quantity

  • Priming the hydraulic system

Hydraulic Pressure Checks

  • Minimum and maximum operating pressure

  • Trouble signs from low or high pressure

  • When to service the pump or valve body

Troubleshooting Common Issues For Twin Disc MG5114A Marine Gear

Hard Shifting or No Engagement

  • Possible causes: low hydraulic pressure, control valve issues

  • Solutions: check solenoids, check fluid level

Slipping in Forward or Reverse

  • Possible causes: worn clutch discs, overheating

  • Solutions: inspect oil, check clutch pack wear

Abnormal Noise or Vibration

  • Causes: misalignment, bearing failure, gear backlash

  • Inspection steps and possible fixes

Oil Leaks

  • Common leak points (input seal, output flange, oil pan gasket)

  • Proper seal replacement guidance

  • Thread sealant and gasket best practices

Removing and Reinstalling the MG5114A Transmission

Removal Procedure For Twin Disc MG5114A Marine Gear

  • Disconnecting control cables and lines

  • Supporting transmission weight safely

  • Removing bolts from bellhousing and mounts

Installation Procedure For Twin Disc MG5114A Marine Gear

  • Flywheel housing alignment

  • Bolt torque and sequence (general reference)

  • Reconnecting hydraulic lines and linkage


                                  

Inspecting Internal Components For Twin Disc MG5114A Marine Gear

Clutch Pack Inspection

  • Signs of wear or heat damage

  • Replacement guidelines (replace as a pack)

Gear Teeth and Bearing Condition

  • Pitting, scoring, or spalling

  • Proper visual inspection techniques

Output Shaft and Oil Seals

  • Endplay checks

  • Seal wear and replacement advice

Hydraulic Control System Overview For Twin Disc MG5114A Marine Gear

Control Valve and Actuator Functions

  • Gear shift logic (F-N-R)

  • Troubleshooting valve body issues

Oil Pump Functionality

  • Gear or vane-type pump explanation

  • Symptoms of a failing pump

Servicing the Valve Body

  • Disassembly precautions

  • Cleanliness and reassembly tips

Parts Replacement and Rebuild Kits For Twin Disc MG5114A Marine Gear

Most Common Replacement Parts

  • Clutch discs and separator plates

  • Gaskets and seals

  • Bearings and thrust washers

Recommended Rebuild Kits

  • What’s included in a typical rebuild kit

  • OEM match aftermarket options from Diesel Pro Power

  • When to choose a full rebuild vs. component service

Complete Rebuilt Transmissions

  • Advantages for high-hour or damaged units

  • When a replacement is more cost-effective than a repair

Storage, Shipping, and Long-Term Maintenance For Twin Disc MG5114A Marine Gear

Proper Storage Practices

  • Sealing ports

  • Using desiccant or anti-corrosion sprays

Shipping Considerations

  • Crating and lifting points

  • Labeling hydraulic line locations

Off-Season Maintenance

  • Draining fluids

  • Periodic rotation of shafts

50 FAQs – Twin Disc MG5114A Marine Transmission

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