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Rebuild Kit and Aftermarket Parts Overview For Allison M & MH Marine Transmissions

July 17, 2025

Introduction


What’s Included in a Standard Rebuild Kit For Allison M & MH Marine Transmissions


Clutch-Related Components


Gaskets and Seals


Bearings and Bushings


Hardware


Advantages of Aftermarket Parts Over OEM


Common Wear and Replacement Parts


Clutch Components


Bearings


Seals and Rings


Thrust Washers


Gaskets and Fasteners


Recommended Fluids and Filter Replacements


Transmission Models Supported


M Series


MH Series


How to Identify the Correct Rebuild Kit


Additional Parts Available at Diesel Pro Power


FAQ – Frequently Asked Questions


Additional Resources for Allison M & MH Marine Transmissions


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Rebuild Kit and Aftermarket Parts Overview For Allison M & MH Marine Transmissions

Parts and Component Replacement Guide For Allison M & MH Marine Transmissions

July 17, 2025

Introduction


1. Manual & Tools – Essential Reference and Equipment


2. Rebuilt Allison M & MH Gears – When to Replace the Entire Transmission


3. Overhaul Kit – Complete Seal and Gasket Replacement


4. Individual Seals – Fixing Localized Leaks


5. Clutch Plate – Worn or Burnt Clutches


6. Hydraulic Pump – Pressure Delivery System


7. Selector Valve & More – Control System Component


8. Transmission Bearings – Reducing Friction and Load Support


9. Sleeve, Ring – Shaft Support and Load Distribution


10. Locknut – Retaining Components Under Torque


11. Washer – Load Spreading and Thrust Control


12. Oil Strainer – Protecting the Hydraulic System


13. Spring & Bolt – Clutch and Valve Assemblies


14. Oil Cooler & Filter – Managing Heat and Cleanliness


15. Coupling – Connecting the Propeller Shaft


Final Notes On Component Replacement


When to Choose Individual Parts vs. Rebuild Kits


Conclusion


Additional Resources for Allison M & MH Marine Transmissions


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Parts and Component Replacement Guide For Allison M & MH Marine Transmissions

50 FAQs – Frequently Asked Questions For Allison M & MH Marine Transmissions

July 17, 2025

Introduction


General Operation FAQs For Allison M & MH Marine Transmissions


1. What do the designations "M" and "MH" mean?


2. What types of gear reductions are available?


3. Can these transmissions accommodate both left-hand and right-hand engine rotation?


4. Are these transmissions suitable for both pleasure and commercial vessels?


5. What kind of clutches are used?


Installation and Setup FAQs For Allison M & MH Marine Transmissions


6. How is the transmission mounted?


7. Does the transmission use the same oil as the engine?


8. What is the oil capacity?


9. Where is the oil dipstick located?


10. What type of oil filter is used?


Operation and Usage FAQs For Allison M & MH Marine Transmissions


11. Can you shift from forward to reverse at any speed?


12. What happens if I try to tow the boat with the engine off?


13. Is full torque shifting recommended?


14. What does the selector valve do?


15. How is the selector valve actuated?


Maintenance FAQs For Allison M & MH Marine Transmissions


16. How often should the oil be changed?


17. What is the correct oil level check procedure?


18. What are signs of oil contamination?


19. Can I reuse oil if it looks clean?


20. How should I store a transmission long-term?


Emergency Use and Troubleshooting FAQs For Allison M & MH Marine Transmissions


21. What is the "Get Home" emergency feature?


22. Can I engage reverse in emergency mode?


23. What should I do if the oil pressure is low?


24. Why is the transmission overheating?


25. What are symptoms of worn clutch plates?


Disassembly and Overhaul FAQs For Allison M & MH Marine Transmissions


26. Are special tools required to overhaul the transmission?


27. What parts are typically replaced during a rebuild?


28. What bearing inspection criteria should I follow?


29. Can I reuse clutch plates?


30. How do I clean and inspect oil passages?


Technical Specifications FAQs For Allison M & MH Marine Transmissions


31. What is the max input torque rating?


32. What’s the max input speed?


33. What is the oil pressure in forward?


34. What is the oil pressure in reverse?


35. What are the recommended shaft horsepower limits?


Torque, Fasteners & Assembly FAQs For Allison M & MH Marine Transmissions


36. What torque spec is used for the output flange nut?


37. Are spanner nuts used?


38. How is backlash adjusted?


39. Should I reuse a staked nut?


40. Is Loctite or thread sealant recommended?


Clutch and Hydraulic System FAQs For Allison M & MH Marine Transmissions


41. How are the clutches engaged?


42. What happens if a dump valve fails?


43. Are clutches adjustable?


44. Can I rebuild the flywheel clutch?


45. How does the hydraulic system work?


Identification & Model-Specific FAQs For Allison M & MH Marine Transmissions


46. Where is the serial number located?


47. What does the “R” in MH25R mean?


48. Can I upgrade from an M to an MH model?


49. Is there a parts catalog available?


50. Where can I find overhaul procedures?


Closing Note


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50 FAQs – Frequently Asked Questions For Allison M & MH Marine Transmissions

Why Diesel Pro Power is the Only Global Source with Detroit Diesel 16V149 Overhaul Kits In Stock and Ready to Ship

July 16, 2025

The Detroit Diesel 16V149: The Ultimate Heavy-Duty Engine


What Makes the 16V149 Special


Where You’ll Find These Titans


Why Finding Overhaul Kits for the 16V149 is Practically Impossible


The Engine is Out of Regular Production


Turbo vs. Non-Turbo Adds Another Layer of Difficulty


The Diesel Pro Power Difference: One of the Only Companies in the World With These Kits In Stock


Why This Matters: The Real Cost of Downtime


What’s Actually In Our 16V149 Overhaul Kits


Each Diesel Pro Power 16V149 Kit Includes:


Why Most Companies Don’t Stock These Kits — and Why We Do


The Financial Risk is Too Big for Most Distributors


It’s Logistically Complex


Turbocharged vs. Non-Turbo: We Stock Both — Because They’re Not the Same


Trusted By Marine and Industrial Operators Worldwide


Technical Expertise You Won’t Find Anywhere Else


Two-Stroke Engine Demands


Compression Matching


Fast Shipping, Worldwide — Because Downtime is the Real Enemy


Protect Your Rebuild — Why We Only Use Premium Components


Conclusion: The Only Real Choice for Detroit Diesel 16V149 Overhauls


Other Parts Diesel Pro Power Carries For The Detroit Diesel 16V149


Additional Resources For The Detroit Diesel 149 Series


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Why Diesel Pro Power is the Only Global Source with Detroit Diesel 16V149 Overhaul Kits In Stock and Ready to Ship

Why Diesel Pro Power is the Only True Source for Detroit Diesel 12V149 Overhaul Kits — In Stock and Ready to Ship

July 16, 2025

Why Diesel Pro Power is the Only True Source for Detroit Diesel 12V149 Overhaul Kits — In Stock and Ready to Ship


The Detroit Diesel 12V149: A Legend of Industrial Power


Key Specs That Made History


Where You’ll Find Them Today


Why the 12V149 is So Difficult to Support


These Engines are Rare and Out of Regular Production


Turbo and Non-Turbo Differences Add Complexity


Why Diesel Pro Power is Different: The World’s True Stocking Source


Why This Matters for Your Operation


What’s Inside Our Detroit Diesel 12V149 Overhaul Kits


Premium Components Include:


Turbo vs. Non-Turbo: We Stock Both


Why Most Companies Can’t — or Won’t — Stock These Kits


Enormous Inventory Risk


Complex Global Logistics


The Diesel Pro Power Difference: Why We’re Trusted Worldwide


Actual In-Stock Inventory


Fast Shipping, Global Reach


Unmatched Technical Support


Avoid the Disaster of Mismatched or Delayed Kits


Serving the World’s Most Demanding Industries


A Few Words on Why We Only Stock Premium Kits


Conclusion: If You Operate a Detroit Diesel 12V149, You Can’t Afford to Wait


Other Parts That We Carry For Detroit Diesel 12V149


Additional Resources For The Detroit Diesel 12V149


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Why Diesel Pro Power is the Only True Source for Detroit Diesel 12V149 Overhaul Kits — In Stock and Ready to Ship

Why Diesel Pro Power is One of the Only Companies in the World with Detroit Diesel 149 Overhaul Kits Ready to Ship

July 16, 2025

The Legendary Detroit Diesel 149 Series


Key Characteristics


Why Detroit Diesel 149 Overhaul Kits Are So Hard to Find


Out of Production for Decades


Extremely Low Volume


Complex, Model-Specific Kits


Why Diesel Pro Power is Different


Built for Urgent Operations


What’s Inside Our Detroit Diesel 149 Overhaul Kits


Major Components


Turbo vs. Non-Turbo


Why So Few Companies Carry These Kits


Inventory Cost and Risk


Global Logistics Challenges


The Cost of Not Having Kits on Hand


Global Reach: From Miami to Manila


Unmatched Expertise With the Detroit Diesel 149


Two-Stroke Specific Challenges


Compression Matching


Long-Term Warranty Support


Why Marine and Industrial Operators Trust Diesel Pro Power


We Actually Stock These Kits


We Ship Fast


We Protect Your Investment


We Know These Engines


Conclusion: There’s Simply No Substitute


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Why Diesel Pro Power is One of the Only Companies in the World with Detroit Diesel 149 Overhaul Kits Ready to Ship