Twin Disc MG5090A Marine Transmission Parts - Overhaul Plate Kit Section

Overhaul Plate Kit Catalog (MG5090 · MG5090A)

This section gives you a clear, catalog-style path to the two essentials for servicing the Twin Disc MG5090A (and MG5090) clutch and sealing system: the Overhaul Plate Kit and the Gasket & Seal Kit . Each item below is presented the same way— what the part is , what it includes , and the signs you might need to change it —so you can validate the repair plan before opening the gear. Focus stays on the MG5090A platform; simply confirm your model, ratio, and tag details, then use the fitment and installation notes to select the correct kit and complete the job with confidence.

Overhaul Plate Kit — MG5090A 

What it is
A matched clutch plate pack engineered for the MG5090A’s forward and reverse clutches to restore designed torque capacity, consistent engagement, and stable operating temperatures.

What it includes

• Friction plates for forward and reverse clutch packs (MG5090A spec)
  
  

• Steel separator plates matched to MG5090A stack dimensions
  
  

• Pack arrangement designed to achieve the correct stack height for MG5090A builds
  
  

Signs you might need to replace

• Engine RPM rises without proportional vessel speed (slippage under throttle)
  
  

• Delayed, harsh, or chattering engagement when shifting into forward or reverse
  
  

• Burnt odor/darkened oil; friction debris present in filter or screen
  
  

• Proper line pressure observed, but hold is weak and oil temperature climbs quickly
  
  

• Visual inspection shows glazed frictions or blue/spotted steels
  
  

Fitment notes

• Confirm model (MG5090A vs. MG5090) , reduction ratio , and serial/build data ; internal clutch counts and stack heights can vary by configuration.
  
  

• If the transmission history includes overheating or contaminated oil, plan to pair the plate kit with fresh seals to protect hydraulic integrity.
  
  

Installation notes

• Pre-soak friction plates in approved marine transmission oil; maintain exact plate order/orientation during assembly.
  
  

• Measure and record stack height and pack clearances; compare to spec before closing the case.
  
  

• Inspect the clutch drum and hub splines; address galling or step wear to prevent rapid re-failure.
  
  

• After assembly, pressure-test forward and reverse at idle and increased RPM to verify apply pressures and engagement quality.
  
  

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Gasket & Seal Kit — MG5090A

What it is
A complete sealing package for MG5090A service that replaces aged elastomers and static gaskets to stop leaks and maintain hydraulic efficiency after internal work.

What it includes

• Input/output shaft oil seals (as applicable to MG5090A build)
  
  

• O-rings and backup rings for control valves, pistons, and service plugs
  
  

• Cover and inspection plate gaskets
  
  

• Sealing washers as required by MG5090A configuration
  
  

Signs you might need to replace

• Oil seepage at shaft ends, inspection covers, or control housings
  
  

• Erratic/low apply pressures suggesting internal bypass or leakdown
  
  

• Any time the housing is opened for clutch service or internal inspection
  
  

• Evidence of water intrusion or emulsified oil (replace seals and identify source)
  
  

Fitment notes

• Designed for MG5090A ; compatible MG5090 versions available—verify serial/build to match lip-seal dimensions and gasket profiles.
  
  

Installation notes

• Clean all sealing surfaces thoroughly; remove old gasket material without scratching.
  
  

• Lightly lubricate O-rings; protect lip seals when passing over splines/keyways (use guide sleeves where appropriate).
  
  

• Verify breather condition—restricted breathers can force oil past otherwise healthy seals.
  
  

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Why Buy MG5090A Overhaul Parts from Diesel Pro Power

Product Matching & Verification

What it means for you
First-time-right kit selection. Provide your model, ratio, and serial/build data and we’ll confirm clutch pack arrangement and seal dimensions specific to MG5090A before fulfillment.

Marine-Grade Quality & Packaging

What it means for you
Friction and steel plates arrive flat, clean, and protected; seals are fresh and individually packed to prevent contamination—ready for bench work the moment you open the box.

Technician-Ready Catalog Format

What it means for you
Clear “ what it is / what it includes / signs you might need it ” structure helps validate your diagnosis quickly and minimize downtime on the dock or in the yard.

One-Stop Convenience

What it means for you
Pair the Overhaul Plate Kit with the Gasket & Seal Kit so you have everything needed to complete the MG5090A service without mid-job sourcing.

Experienced Support, Trusted by 40,000+ Customers

What it means for you
Have your tag details ready—our marine-focused team will help confirm stack targets, seal selections, and practical install notes so you can finish the job with confidence.