Recommended Spare Parts and Kits for Twin Disc MG516 Marine Gear

April 1, 2025

 


Introduction


Rebuild Kits for Twin Disc MG516 Marine Gear


What Is a Rebuild Kit?


What’s Typically Included in an MG516 Rebuild Kit?


Types of Rebuild Kits Available


Why Use a Pre-Packaged Kit?


Where to Buy MG516 Rebuild Kits


Commonly Replaced Parts for Twin Disc MG516 Marine Gear


1. Filters


2. Gasket Sets


 


3. Shaft Seals


4. Clutch Friction and Steel Plates


5. Control Valve Components


6. Bearings and Thrust Washers


When to Replace vs Rebuild a Twin Disc MG516


Rebuild the MG516 When:


Replace the MG516 When


Cost Comparison: Rebuild vs Replacement


Downtime Considerations


Rebuild Lead Time


Replacement Lead Time


Maintenance Stock Recommendations for MG516 Operators


Emergency Spare Parts


Long-Term Support Inventory


Quality Considerations: OEM vs Aftermarket


OEM (Twin Disc)


Aftermarket (Diesel Pro Power)


Tips for Successful Rebuild Planning


Summary: Recommended Spare Parts and Kits for Twin Disc MG516 Marine Gear


Key Takeaways:


Videos About Twin Disc Transmissions


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Recommended Spare Parts and Kits for Twin Disc MG516 Marine Gear

Reassembly Tips and Best Practices for Twin Disc MG516 Marine Gear

April 1, 2025

Introduction


Torque Specifications for Twin Disc MG516 Marine Gear


Why Torque Specifications Matter


General Torque Guidelines (Typical MG516 Values)


Component


Torque Specification


Using a Torque Wrench Correctly


Torque Sequencing Examples


Fastener Cleaning and Preparation


Use of Gasket Sealant and RTV for Twin Disc MG516 Marine Gear


Why Sealants Are Critical


Types of Sealants Used in MG516 Service


Sealant Type


Use Case


Best Practices: Using Gasket Sealants on MG516


Common Sealant Mistakes to Avoid


Pre-Startup Checks for Twin Disc MG516 Marine Gear


Pre-Startup Inspection Categories


Step-by-Step Final Inspection Checklist


✅ 1. Confirm All Fasteners Are Torqued

✅ 2. Oil Filled to Proper Level

✅ 3. New Filter Installed and Primed

✅ 4. Control Valve and Solenoids Connected

✅ 5. Rotate Transmission Manually (If Possible)

✅ 6. Inspect Seals and Breathers

✅ 7. Verify Alignment with Prop Shaft

✅ 8. Setup for Initial Start

Initial Startup Procedure


Pressure and Temperature Monitoring


Post-Startup Torque Recheck


Real-World Reassembly Oversights and Lessons


Example 1: Leaking Flange After Sea Trial


Example 2: Oil Starvation at Startup


Example 3: No Reverse After Rebuild


Final 30-Point Reassembly and Startup Checklist


Summary: Reassembly Tips and Best Practices for Twin Disc MG516 Marine Gear


Videos About Twin Disc Transmissions


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Reassembly Tips and Best Practices for Twin Disc MG516 Marine Gear

Control Valve Maintenance for Twin Disc MG516 Marine Gear

April 1, 2025

Introduction


Overview: How the MG516 Control Valve Works


Solenoid and Valve Cleaning for Twin Disc MG516 Marine Gear


When to Service the Valve Assembly


Components in the Control Valve System


Tools and Supplies Needed


Step-by-Step: Solenoid and Valve Removal


Cleaning Procedures


Reassembly Tips


Testing Shifting Operation for Twin Disc MG516 Marine Gear


Manual Shift Control Systems


How to Troubleshoot Manual Shifting


Electronic Shift Control Systems


Common Electronic Shift Faults


Symptom


Probable Cause


Step-by-Step Electronic Diagnostics


Simulating Manual Shift


Preventative Maintenance for Control Valve System


Control Valve Rebuild Kits and Replacement Parts


Real-World Shift Troubleshooting Examples


Case Study 1: Commercial Ferry Stuck in Neutral


Case Study 2: Trawler with Delayed Reverse


Case Study 3: Gearbox Slams Into Gear


Final Post-Service Checklist


Summary: Control Valve Maintenance for Twin Disc MG516 Marine Gear


Videos About Twin Disc Transmissions


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Control Valve Maintenance for Twin Disc MG516 Marine Gear

Cooler and Oil Circulation System for Twin Disc MG516 Marine Gear

April 1, 2025

Introduction


Overview of the MG516 Oil Circulation and Cooling System


Key Components:


How Oil Flows Through the MG516 System


Heat Exchanger Inspection for Twin Disc MG516 Marine Gear


When to Inspect or Service the Heat Exchanger


Tools and Supplies Needed


Inspection Procedure: External and Visual


Disassembly and Internal Cleaning


Oil Flow Testing for Twin Disc MG516 Marine Gear


When to Perform an Oil Flow Test


Tools You’ll Need


Flow Test Locations (MG516)


Acceptable Flow Rates (Typical)


Oil Flow Testing Procedure


Diagnosing Poor Oil Flow


Corrective Actions


Preventative Cooling System Maintenance Tips


Warning Signs of Cooling System Trouble


Case Studies and Field Examples


Case Study 1: Trawler with Intermittent Overheating


Case Study 2: Charter Vessel with Low Flow at Idle


Final Checklist for Cooling System Service


Summary: Cooling and Oil Circulation System for MG516 Marine Gear


Videos About Twin Disc Transmissions


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Cooler and Oil Circulation System for Twin Disc MG516 Marine Gear

Output Shaft and Rear Housing Maintenance for Twin Disc MG516 Marine Gear

April 1, 2025

Introduction


Rear Output Assembly Overview for Twin Disc MG516 Marine Gear


Bearing and Seal Inspection for Twin Disc MG516 Marine Gear


When to Inspect the Output Shaft Bearings and Seal


Tools and Supplies Needed


Rear Bearing Types and Function


How to Inspect Output Shaft Bearings


When to Replace Bearings


Output Shaft Seal Inspection and Replacement


Signs of Seal Failure


How to Replace the Output Shaft Seal


Preventing Premature Seal Wear


Shaft Alignment and Runout for Twin Disc MG516 Marine Gear


Why Alignment Matters


Measuring Shaft Runout


Shaft Alignment to Propeller Shaft


Real-World Failures Due to Neglected Rear Housing Maintenance


Case Study 1: Tugboat Output Seal Leak


Case Study 2: Vibrating Crew Boat at Cruise Speed


Rear Housing Reassembly Tips


Final Inspection Checklist


Summary: Output Shaft and Rear Housing Maintenance for Twin Disc MG516 Marine Gear


Videos About Twin Disc Transmissions


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Output Shaft and Rear Housing Maintenance for Twin Disc MG516 Marine Gear

Clutch and Gear Inspection for Twin Disc MG516 Marine Gear

April 1, 2025

 


Introduction


Clutch Pack Inspection for Twin Disc MG516 Marine Gear


When to Inspect the Clutch Packs


Tools and Supplies You’ll Need


Accessing the Clutch Packs


Understanding the Clutch Stack


Wear Indicators to Watch For


Measuring Clutch Pack Clearance


Reassembly Tips


Break-In Procedure for New Clutches


Gear Train and Tooth Wear Inspection for Twin Disc MG516 Marine Gear


 


When to Inspect Gears


Components in the Gear Train


Gear Tooth Wear Types and Identification


How to Inspect Gear Condition


Gear Pitch and Contact Pattern Testing


Measuring Gear Backlash in Twin Disc MG516 Marine Gear


Tools Required


Measurement Procedure


Typical Backlash Tolerance


What Causes Backlash Problems?


Gear and Shaft Inspection Best Practices


Shaft Endplay Measurement


Bearing and Race Inspection


Rebuilding the Gear Train


Real-World Gear Failure Examples


Case Study 1: Offshore Crew Boat with Metallic Noise


Case Study 2: Trawler with Gearbox Overheating


Maintenance Intervals for Gear and Clutch Inspection


Final Inspection Checklist


Summary: Why Clutch and Gear Inspection Matters


Videos About Twin Disc Transmissions


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Clutch and Gear Inspection for Twin Disc MG516 Marine Gear