Twin Disc MG520 Marine Transmission Parts for Canada - Overhaul Plate Kit Section

Twin Disc MG520 Marine Transmission Parts — Overhaul Plate Kit Section

This catalog section is dedicated to the clutch and sealing components most shops stage together when servicing Twin Disc MG520 and MG520-1 marine gears. Use it to quickly identify what the part is, what’s included, typical symptoms that point to replacement, and key selection notes so you can get the right kit the first time and return your vessel to smooth, repeatable engagement. Sourcing here from Diesel Pro Power means MG520-specific curation, clear specifications, quality components selected for correct stack height and material compatibility, fast fulfillment to keep downtime low, and the confidence of 40,000+ satisfied customers who trust our marine gear expertise.

Overhaul Plate Kit — MG520 & MG520-1

What it is:
A complete clutch “plate pack” engineered for MG520/MG520-1 service. It restores the friction interface that transmits engine torque through the gear.

What it includes:
Matched sets of friction plates and steel separator plates manufactured to the correct thickness and surface finish for MG520 specifications. Kits are balanced as a set so stack height is within spec once installed.

What it fixes (common symptoms):

• Slow or slipping engagement under load: RPM rises without corresponding thrust, especially when maneuvering or accelerating.
  
  

• Harsh, chattering engagement: Vibration or shudder entering gear due to glazed or heat-checked plates.
  
  

• Overheating and burnt odor in the gear oil: Thermal breakdown after prolonged slipping or misadjustment.
  
  

• Metallic “blackened” oil or fine debris in the screen: Wear particulates from friction material and steels.
  
  

Why replacement matters:
Correct plate coefficient of friction and stack height are essential in MG520 torque transmission. Running on thinned, warped, or contaminated plates risks heat soak, accelerated wear on the hub and drum, and lost schedule time.

Selection notes:

• Model focus: Choose the kit labeled for MG520/MG520-1 only; plate counts and thicknesses are tuned to this gearbox.
  
  

• Operating profile: Heavy towing, frequent docking, or high-hour shuttle service benefit from a fresh plate pack sooner than light-duty pleasure craft.
  
  

• Oil health: If plates show heat spotting, plan a full drain, flush, and filter change to protect the new pack.
  
  

Installation pointers (at a glance):

• Measure stack height: Verify total installed height meets MG520 spec after soaking/friction pre-lube.
  
  

• Inspect mating hardware: Check clutch drum and hub splines for step wear; replace if out of tolerance.
  
  

• Break-in discipline: Follow a controlled break-in with conservative load cycles to seat the new friction surface.
  
  

Gasket & Seal Kit — MG520 & MG520-1

What it is:
A complete reseal set designed for MG520 housings and covers to stop leaks and stabilize operating pressure.

What it includes:
Application-correct case gaskets, shaft seals, O-rings, and sealing washers for typical split points and service interfaces on MG520/MG520-1.

What it fixes (common symptoms):

• Oil drips at bellhousing or output: Telltale film on the case or bilge sheen points to tired lip seals.
  
  

• Pressure instability or aeration: Hardened O-rings can pull air, causing delayed engagement and noise.
  
  

• Seepage after a clutch job: Reusing compressed gaskets often leads to weeping after heat cycles.
  
  

Why replacement matters:
Maintaining correct oil level and pressure is essential for clutch life. A reseal during a plate change prevents future downtime and keeps the bilge clean.

Selection notes:

• Case depth & ratio aren’t the driver: For MG520/MG520-1, use the dedicated reseal set; it’s built around the housing pattern, not ratio.
  
  

• Pair with a filter and screen service: New seals plus clean filtration help the fresh clutch pack run cooler and cleaner.
  
  

Installation pointers (at a glance):

• Prep surfaces: Remove old gasket residue without gouging; confirm flatness at mating flanges.
  
  

• Lube lip seals: Pre-lube and verify correct orientation to avoid early wear.
  
  

• Torque pattern: Use proper cross-pattern and spec to avoid case distortion and seepage.
  
  

Rubber Block — MG520 Mount Interface

What it is:
A high-durometer rubber block used in the gear’s mount interface to manage torsional input and isolate vibration.

Where it’s used on MG520/MG520-1:
At designated mount points to keep the gear properly supported and aligned relative to the engine and shaft line.

What it fixes (common symptoms):

• New vibration or “buzz” at certain RPM: Flattened or cracked blocks transmit harmonics into the hull.
  
  

• Alignment drift: Premature coupling wear or recurring alignment corrections can stem from collapsed mounts.
  
  

• Clunk on shift: Excess gear movement as load transfers forward/aft indicates deteriorated isolation.
  
  

Why replacement matters:
Proper isolation preserves clutch life, minimizes companion flange wear, and keeps the vessel quiet. A fresh set of blocks stabilizes the gear after a major service.

Selection notes:

• Match hardness to the application: Heavier vessels and higher torsional input benefit from the specified compound for MG520.
  
  

• Replace in sets: Mixing old and new supports can twist the housing or mask true alignment.
  
  

Installation pointers (at a glance):

• Support the gear safely: Relieve weight before removal.
  
  

• Set alignment after replacement: Always re-check coupling alignment warm and under typical load if feasible.
  
  

Quick Service Combinations for MG520/MG520-1

• Performance refresh: Overhaul Plate Kit + Gasket & Seal Kit
  Ideal when you’re chasing slip, heat, or shudder and want to reset the friction surface and sealing integrity in one visit.
  
  

• Leak stop & pressure restore: Gasket & Seal Kit (with filter/screen service)
  For stable pressure, clean bilge, and long-term clutch health—often paired with fresh oil after diagnostics.
  
  

• Vibration and alignment tidy-up: Rubber Blocks (with alignment check)
  Quiet the drivetrain, protect bearings, and prepare the gear for many more hours of smooth duty.
  
  

How to Choose the Right Kit (MG520 Focus)

Confirm the model tag: Verify MG520 or MG520-1 on the gear tag before ordering.
Describe symptoms: Slipping, heat, or shudder → plate kit; wet spots or pressure anomalies → reseal; vibration/alignment drift → rubber blocks.
Consider duty cycle: Tugs, ferries, workboats, and charter craft often benefit from a full plate + reseal at the same time to minimize repeat haul-outs.
Plan consumables: Have approved oil, filters, and cleaning supplies on hand; a clean system is essential for new components.

Why Buy Your MG520 Kits from Diesel Pro Power

MG520-specific curation: Every kit shown here is selected for MG520/MG520-1 fit and performance, minimizing guesswork and returns.
Quality you can feel: Frictions and steels are sourced to deliver correct coefficient of friction and stack height, while seals meet material compatibility for marine service.
Availability and speed: Streamlined logistics and deep inventory across Twin Disc service items help you schedule with confidence.
Trusted by 40,000+ satisfied customers: Commercial operators, shipyards, and private owners rely on Diesel Pro Power for consistent fit and long service life.