Twin Disc MG509 Marine Transmission Parts — Bearing Kit Catalog

Welcome to the Twin Disc MG509 Bearing Kit Catalog from Diesel Pro Power, your trusted global source for high-quality marine transmission parts. The MG509 is one of the most durable and widely used Twin Disc models, known for its reliability in marine and industrial applications. Whether you’re rebuilding a commercial vessel transmission or performing preventive maintenance on a workboat, Diesel Pro Power provides everything you need — bearing kits, gasket and seal kits, oil strainers, and more — all designed for perfect fit and lasting performance.

With over 40,000 satisfied customers in 180 countries, Diesel Pro Power is the name professionals trust for dependable quality, fast global delivery, and unmatched customer support.

Bearing Kits for Twin Disc MG509

The MG509 transmission comes in two versions — the Shallow Case and the Deep Case — each designed for specific gear ratio ranges. Choosing the correct kit ensures proper fit and long-term performance.

Bearing Kit — Shallow Case (Ratios 1.45:1 to 3.38:1)

The Shallow Case Bearing Kit is built for MG509 models operating with lower to mid-range ratios. It contains all major bearings and components required to restore smooth operation and eliminate vibration or noise caused by worn bearings. This kit ensures consistent oil pressure, precise gear engagement, and long service life under continuous-duty operation.

Features:

• Designed for transmissions with gear ratios from 1.45:1 through 3.38:1

• Includes premium bearings for input, output, and intermediate shafts

• Helps prevent bearing noise, overheating, and gear wear

• Manufactured to meet exact OEM specifications for balance and durability

This kit is ideal for operators seeking quiet operation, smooth shifting, and dependable performance in everyday marine use.

Bearing Kit — Deep Case (Ratios 3.83:1 to 4.95:1)

The Deep Case Bearing Kit is made for MG509 models running higher reduction ratios. These transmissions experience greater internal torque and stress, so the bearings in this kit are built for enhanced load capacity and longevity.

Features:

• Designed for MG509 gear ratios between 3.83:1 and 4.95:1

• Equipped with heavy-duty bearings capable of handling increased thrust loads

• Ensures smooth rotation, proper gear alignment, and stable oil flow

• Maintains efficient operation under continuous heavy-duty or high-power use

This kit offers the strength and precision required for vessels that operate under high load or extended-duty conditions, ensuring lasting reliability even in demanding marine environments.

Gasket and Seal Kits for MG509

Replacing bearings without new gaskets and seals can lead to oil leaks and pressure loss. Diesel Pro Power provides complete gasket and seal kits for both shallow and deep case models, ensuring complete sealing and leak prevention throughout the transmission.

Gasket and Seal Kit — Shallow Case (Ratios 1.45:1 to 3.38:1)

Designed to pair perfectly with the shallow case bearing kit, this gasket set includes all necessary seals, O-rings, and gaskets to ensure proper sealing at every connection point. It restores the original oil-tight integrity of your MG509 transmission and protects new bearings from contamination.

Gasket and Seal Kit — Deep Case (Ratios 3.83:1 to 4.95:1)

For deep case transmissions, this gasket kit ensures complete coverage and proper sealing across the larger case housing. Built from premium, oil-resistant materials, it prevents leaks and helps maintain correct oil pressure.

Key Benefits of Both Kits:

• Provides complete sealing coverage for input, output, and intermediate housings

• Prevents oil leaks and contamination

• Extends transmission service life

• Designed for easy installation and reliable performance

Supporting Components for a Complete MG509 Rebuild

Diesel Pro Power also offers essential accessories to support a complete rebuild or maintenance service for your Twin Disc MG509 transmission.

Oil Strainer

The oil strainer keeps your transmission oil clean by filtering out metal particles and contaminants before they reach critical components. Replacing the oil strainer during a bearing or seal service ensures clean lubrication, stable pressure, and longer component life.

Benefits:

• Protects bearings and gears from debris

• Maintains consistent oil flow

• Reduces wear and overheating

• Helps extend the overall lifespan of the transmission

Rubber Block Mount

The rubber block mount helps isolate vibration between the transmission and hull structure. Over time, rubber mounts can harden or crack, increasing vibration and noise. Replacing them restores smooth operation and protects internal seals and gaskets from vibration-related damage.

Benefits:

• Reduces noise and vibration

• Protects internal components from shock loads

• Improves comfort and overall smoothness of operation

Oil Cooler and Lines

Proper oil cooling is critical to bearing and clutch life. Diesel Pro Power offers replacement oil coolers and hose assemblies designed for the MG509, ensuring the transmission stays at the correct operating temperature and performs efficiently under load.

Benefits:

• Prevents overheating

• Maintains optimal oil viscosity

• Reduces stress on internal components

• Improves transmission efficiency and durability

When to Replace Bearings and Seals

Over time, bearings in marine transmissions naturally wear due to heat, load, and contamination. Common signs it’s time to rebuild your MG509 with a new bearing kit include:

• Unusual or increasing transmission noise

• Oil discoloration or metallic debris in the strainer

• Higher-than-normal operating temperatures

• Vibration or rough engagement during gear shifts

• Oil leaks or reduced oil pressure

Replacing worn bearings and seals restores smooth operation, reduces downtime, and extends the overall life of your Twin Disc MG509 transmission.

Why Choose Diesel Pro Power

Diesel Pro Power has built a reputation as the leading global source for Twin Disc marine transmission parts. Our team specializes in helping customers identify the correct kits and components for their specific applications, providing fast and reliable solutions every time.

What Sets Diesel Pro Power Apart:

• Serving 40,000+ customers across 180 countries

• Premium aftermarket parts built to meet OEM standards

• Fast global delivery and professional packaging

• Knowledgeable support staff ready to assist with product selection

• Complete product coverage for Twin Disc MG509, MG506, MG507, and other legacy models

Keeping Your MG509 Running Strong

A well-maintained MG509 transmission can serve faithfully for decades. When serviced with Diesel Pro Power’s high-quality bearing kits, gasket sets, and filtration components, you can expect:

• Smooth gear operation and reduced vibration

• Improved oil flow and cooling efficiency

• Extended service life of internal components

• Reliable performance for commercial or leisure vessels alike

Diesel Pro Power simplifies the entire maintenance process — providing everything you need, from the smallest gasket to a complete bearing kit, all backed by knowledgeable support and global logistics expertise.

Recommended Service Pairings

To get the most from your bearing replacement, consider servicing these related areas at the same time:

• Replace the oil strainer to ensure clean lubrication

• Inspect and flush the oil cooler to maintain proper temperature control

• Replace the rubber mounts to minimize vibration

• Install new seals and gaskets to prevent future leaks

Combining these preventive steps during a rebuild saves time, protects your investment, and ensures long-term reliability.

Diesel Pro Power — Trusted by Marine Professionals Worldwide

From small fishing boats to large commercial vessels, thousands of marine professionals depend on Diesel Pro Power every day. Our commitment to quality, precision, and reliability has made us the go-to source for parts that keep Twin Disc transmissions performing as designed.

When it’s time to rebuild or service your Twin Disc MG509, choose Diesel Pro Power for:

• Reliable, high-quality components

• Expert customer service

• Global shipping and professional packaging

• A proven track record of trust and satisfaction

Summary

The Twin Disc MG509 Bearing Kit Catalog provides everything needed to maintain or rebuild your transmission with confidence. With Diesel Pro Power, you’ll get top-quality parts, knowledgeable assistance, and the peace of mind that comes with working with the world’s most trusted supplier of Twin Disc marine transmission components.

Choose Diesel Pro Power — where reliability, quality, and expertise keep your transmission performing at its best.