Twin Disc MG5111A Marine Transmission Parts for Australia - Overhaul Plate Kit Section

Twin Disc MG5111 & MG5111A — Overhaul Plate Kit & Angled-Drive Gasket/Seal Kit

Get back crisp shifts and reliable torque transfer on your MG5111 or MG5111A with a purpose-built clutch (overhaul) plate kit and the correct angled-drive gasket/seal kit. This catalog section is designed in a technician-first format so you can identify the right components fast, understand what each kit includes, recognize the signs that service is due, and complete the job with confidence—without chasing part numbers. Whether you’re maintaining a single workboat or standardizing across a fleet, the selections below keep your focus on fit, function, and uptime.

Overhaul Plate Kit for Twin Disc MG5111 / MG5111A

What it is
A matched set of friction and steel plates engineered to restore proper clutch pack clearances, oil flow, and engagement characteristics in MG5111 and MG5111A marine gears. The kit is curated to meet the clutch capacity and thermal requirements of these models, helping prevent slip under load and preserving gear life.

What it includes

• Friction plates manufactured to the correct thickness, flatness, and friction coefficient for MG5111/5111A duty cycles.
  
  

• Steel reaction plates with controlled surface finish to ensure stable coefficient of friction, heat dissipation, and minimal warpage under repeated engagements.
  
  

• Application-specific count and stacking sequence guidance to achieve target pack height and clutch release clearance.
  
  

• Recommended pre-soak and run-in instructions so the friction material beds correctly on first operation.
  
  

What it fixes

• Slipping under throttle: RPM rises without proportional boat speed due to worn friction material or glazed steels.
  
  

• Harsh or delayed engagement: Erratic take-up caused by uneven plate wear, wrong clearances, or contaminated surfaces.
  
  

• Overheating of transmission oil: Excessive clutch slip generating heat that stresses seals and bearings.
  
  

• Metallic debris in sump/filter: Evidence of plate or steel breakdown pointing to an overdue clutch service.
  
  

Signs you may need it

• Measurable loss of speed at a familiar throttle setting.
  
  

• Increased engagement time moving from neutral to ahead/astern.
  
  

• Burnt-oil smell after maneuvering or towing.
  
  

• Dark, glittery fluid or recurring filter loading with fine metallics.
  
  

• Previous gasket/seal repairs that didn’t resolve slip (a clue that core clutch surfaces are the issue).
  
  

Key install notes

• Pack height matters: Follow the MG5111/5111A clutch pack height specification; incorrect height leads to either persistent slip (too tall) or drag/overlap (too short).
  
  

• Plate orientation: Some friction cores or steels have a preferred face; match any witness marks or manufacturer arrows.
  
  

• Surface prep: Clean steels thoroughly; replace any with bluing/heat spotting or measurable distortion.
  
  

• Pre-soak: Wet friction plates in the approved oil before assembly to prevent dry engagement on start-up.
  
  

• Torque sequence: Use a star or cross pattern on pressure plate hardware and verify free rotation after torquing.
  
  

Compatibility note
The overhaul plate kit is suitable for both MG5111 and MG5111A. Differences between these models (such as output housing style on the angled-drive 5111A) do not change the clutch pack requirements—but they do affect the gasket/seal selections described below.

Gasket & Seal Kit — MG5111A Angled Drive

What it is
A comprehensive sealing package tailored to the angled-drive output housing used on MG5111A variants. It addresses the specific geometry and shaft presentation unique to the angled configuration, ensuring leak-free operation after service.

What it includes

• Output shaft seals sized and lipped for the MG5111A angled drive to handle axial alignment and dynamic runout properly.
  
  

• Housing gaskets profiled for the angled gear case and cover intersections.
  
  

• O-rings and form-in-place seal substitutes for oil passageways and bearing carriers in the angled output.
  
  

• Selector shaft seals and inspection cover gaskets to resolve nuisance drips.
  
  

• Drain/fill port sealing elements matched to the MG5111A case.
  
  

What it fixes

• Output seal weeping where the shaft exits the angled housing.
  
  

• Case mating surface leaks after disassembly or previous RTV-only repairs.
  
  

• Nuisance drips at inspection plates, selector shafts, or plugs that attract grit and degrade components over time.
  
  

• Air ingestion points that can aerate oil and affect clutch performance.
  
  

Signs you may need it

• Oil film collecting beneath the angled output housing after lay-up.
  
  

• Bilge sheen or oil odor following long transits.
  
  

• Recurrent top-ups with no external mess until operating temperature is reached (thermal expansion opens marginal seals).
  
  

• Dampness around selector shafts or inspection covers.
  
  

Key install notes

• Inspect the shaft: A grooved or pitted output shaft will defeat a new seal—measure and repair/replace as needed.
  
  

• Runout check: Excess runout accelerates lip wear; confirm before final seal seating.
  
  

• Mating surface prep: Remove old gasket material fully; flatness and cleanliness are essential.
  
  

• Seal depth & orientation: Use the correct driver to avoid cocking or lip inversion; lightly oil the lip before install.
  
  

• Fastener torque: Uneven clamp can cause wicking; torque in sequence to spec and recheck after heat cycles.
  
  

Choosing Between the Two (and When to Use Both)

• If your primary complaint is slip, slow engagement, or burnt fluid, start with the overhaul plate kit. Clutch integrity is foundational; sealing won’t correct worn friction.
  
  

• If your primary complaint is leaking or aerated oil, the angled-drive gasket/seal kit is the first move—especially on MG5111A where output geometry is the usual suspect.
  
  

• If both symptoms exist, plan a combined service: reseal the MG5111A output and refresh the clutch packs. Doing both in a single haul-out minimizes downtime and redundant labor.
  
  

Pro Tips to Protect Your Repair

• Oil quality and level: Use the manufacturer-approved oil at the correct level. Low or foamed oil undermines clutch grip and increases heat.
  
  

• Cooling health: Verify oil cooler flow/pressure and cleanliness; marginal cooling shortens plate life.
  
  

• Shift technique: Avoid feathering against heavy load. Smooth, decisive shifts reduce micro-slip and glazing.
  
  

• Post-service break-in: After the plate kit install, perform controlled low-load cycles ahead/astern to seat friction material; re-inspect fluid for debris and proper color.
  
  

• Baseline measurements: Record pack height, freeplay, and pressure readings at service—future diagnostics will be faster and more definitive.
  
  

Why Buy These MG5111 / MG5111A Kits from Diesel Pro Power

• Right kit, first time: Application-specific curation for MG5111 and MG5111A—including the correct angled-drive sealing set—reduces guesswork and rework.
  
  

• Quality you can feel: Friction and steel plates selected for consistent thickness, flatness, and friction behavior—critical for smooth take-up and long life.
  
  

• Proven trust: Backed by 40,000+ satisfied customers who rely on Diesel Pro Power to keep vessels earning.