2017 Kenworth W900 Transmission Fluid & Service

Quick Answer

• Transmission Make/Model: Eaton Fuller Advantage Automated Manual Transmission (AMT), typically an FR Series or similar.
• OEM Fluid Spec: Eaton PS-386 or an approved equivalent synthetic transmission fluid (SAE 50).
• Drain & Fill Capacity: Approximately 13-16 quarts (12.3-15.1 liters) – verify with service manual.
• Full Overhaul Capacity: Approximately 17-20 quarts (16.1-18.9 liters) – verify with service manual.
• Filter OEM Part Number: Verify with dealer or service manual, as specific filters can vary by transmission model and setup.
• Recommended Service Interval: 250,000 miles or 3 years for normal service; 125,000 miles or 1 year for severe duty.

Fluid Type Explained

The 2017 Kenworth W900, if equipped with an Eaton Fuller Advantage Automated Manual Transmission (AMT), relies on a specific synthetic transmission fluid to ensure optimal performance and longevity. The primary OEM fluid specification is Eaton PS-386. This is a purpose-built SAE 50 synthetic fluid designed to handle the heavy demands of commercial trucking and the unique characteristics of Eaton Fuller transmissions.

Why is the correct fluid so critical?

• Lubrication: Heavy-duty transmissions deal with immense internal pressures and friction. The right fluid provides superior lubrication, reducing wear on gears, bearings, and synchronizers.
• Heat Dissipation: Commercial trucks generate significant heat, especially under load. Synthetic fluids like Eaton PS-386 excel at dissipating heat, preventing overheating and premature component failure.
• Viscosity Stability: These fluids maintain their optimal viscosity across a wide range of operating temperatures, ensuring consistent performance in both cold starts and extreme operating conditions.
• Corrosion Protection: They contain additives that protect internal components from rust and corrosion, extending the transmission's lifespan.
• Shift Quality: Proper fluid contributes to smooth and consistent shifting, which is particularly important for an automated manual transmission.

While Eaton PS-386 is the recommended fluid, some approved equivalent synthetic transmission fluids meeting the SAE 50 specification may be used. Always consult your Kenworth owner's manual or an authorized dealer to confirm acceptable alternatives. Never use fluids not approved by Eaton, such as standard engine oil or incorrect ATF types, as this can lead to severe transmission damage and void your warranty.

Service Procedure

Servicing an Eaton Fuller AMT transmission involves either a drain and fill or a full fluid exchange. Given the complexity and importance of these transmissions, it's often best handled by qualified technicians.

Drain & Fill

A drain and fill involves draining the old fluid from the transmission pan and then refilling it with new fluid. This method replaces a significant portion of the old fluid but typically leaves some residual fluid in the torque converter (if equipped) and other internal components. For a 2017 Kenworth W900 with an Eaton Fuller AMT, the drain and fill capacity is approximately 13-16 quarts.

Basic steps for a drain & fill (for informational purposes; professional service recommended):

1. Safely lift and secure the vehicle.
2. Place a suitable drain pan beneath the transmission.
3. Remove the drain plug and allow all fluid to drain completely.
4. Reinstall the drain plug, ensuring a new gasket (if applicable) is used and tightened to spec.
5. Remove the fill plug.
6. Using a pump, add the specified amount of new Eaton PS-386 fluid until it reaches the correct level (usually at the bottom of the fill plug hole or indicated by a dipstick).
7. Reinstall the fill plug.
8. Check for leaks and perform a functional check.

Full Fluid Exchange

A full fluid exchange, often done using specialized equipment, aims to replace nearly all of the old transmission fluid. This is generally preferred for severe duty applications or if there's a concern about contaminants in the old fluid. A "full overhaul capacity" refers to the total volume of fluid the transmission system can hold, which typically comes into play during a complete rebuild or replacement. For an Eaton Fuller AMT, this is approximately 17-20 quarts.

During a full fluid exchange, the transmission filter should always be replaced. Always verify the correct filter OEM part number with a Kenworth dealer or your service manual, as there can be variations.

Service Interval

Adhering to the correct service interval is paramount for the longevity and reliability of your 2017 Kenworth W900's transmission.

• Normal Service: Under normal operating conditions (e.g., highway driving, light loads, regular maintenance), Eaton Fuller AMTs typically recommend a transmission fluid and filter change every 250,000 miles or 3 years, whichever comes first.

• Severe Duty / Towing: If your W900 is frequently subjected to severe operating conditions, such as:

  • Heavy hauling/towing at or near Gross Combination Weight Rating (GCWR)
  • Frequent stop-and-go driving
  • Operation in extreme hot or cold climates
  • Sustained operation over steep grades
  • Off-highway or dusty road operation

  The service interval should be shortened to every 125,000 miles or 1 year, whichever comes first. Refer to your vehicle's maintenance schedule for precise severe duty definitions applicable to your specific setup.

Regular fluid analysis can also help determine the optimal service interval by monitoring fluid degradation and identifying potential internal wear.

Common Transmission Problems for this Generation

While Eaton Fuller AMTs are generally robust, some common issues can arise, particularly in heavy-duty applications:

• Shift Quality Issues: Hesitation, harsh shifts, or failure to engage a gear can often be linked to low or contaminated fluid, worn solenoids, or issues with the transmission control module (TCM) or clutch actuator.
• Fluid Leaks: Seals and gaskets can degrade over time, leading to leaks. Pinpointing the source is crucial to prevent fluid starvation and potential damage.
• Clutch Wear: As a manual transmission with automated shifting, clutch wear is inevitable. If the clutch actuator or clutch itself starts to fail, it can manifest as slipping, poor acceleration, or difficulty engaging gears. Early signs include increased RPMs without corresponding speed gain.
• Sensor Malfunctions: Various sensors (speed, temperature, position) provide critical data to the TCM. A faulty sensor can lead to incorrect shifting, limp mode, or diagnostic trouble codes (DTCs).
• Actuator Problems: The shift actuators and clutch actuator are electro-mechanical components that perform physical shifts and clutch engagement. Failures here can cause a complete loss of gear engagement or improper shifting.
• Cooler Line Issues: The transmission cooler helps regulate fluid temperature. Leaks or blockages in the cooler lines or cooler itself can lead to overheating.

Early detection is key. Pay attention to warning lights, unusual noises, changes in shift feel, or any fluid leaks. Addressing minor issues promptly can prevent more extensive and costly repairs down the road.

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