2022 Peterbilt 579 Transmission Fluid & Service

Quick Answer

• Transmission Make/Model: Eaton Advantage Automated Manual Transmission (AMT) or Eaton Fuller Advantage Manual Transmission (depending on configuration)
• OEM Fluid Spec: Eaton PS-386 (or equivalent synthetic 50 weight transmission fluid meeting Eaton PS-386 requirements)
• Drain & Fill Capacity: Varies by transmission model. Typically 14-17 quarts for Advantage AMTs and 15-20 quarts for Fuller Advantage Manuals. Always verify with your specific vehicle's service manual.
• Full Overhaul Capacity: Varies significantly. Consult a service manual or dealer for exact figures.
• Filter OEM Part Number: No external filter in most Eaton Heavy-Duty transmissions. Internal screens are generally non-serviceable during routine fluid changes. Verify with dealer or service manual if applicable to your specific transmission model.
• Recommended Service Interval:
  • Normal Duty: 250,000 miles or 3 years
  • Severe Duty/Towing: 120,000 miles or 1 year (More frequent for extreme conditions)

Fluid Type Explained

The 2022 Peterbilt 579, a popular choice for long-haul and vocational applications, is often equipped with Eaton transmissions, specifically the Eaton Advantage Automated Manual Transmissions (AMT) or Eaton Fuller Advantage Manual Transmissions. These transmissions are engineered for heavy-duty performance and require specific lubrication to ensure longevity and efficiency.

The critical specification for these transmissions is Eaton PS-386. This is a synthetic 50-weight transmission fluid that provides superior thermal stability, oxidation resistance, and shear stability compared to conventional fluids. The high demands placed on heavy-duty truck transmissions necessitate a fluid that can withstand extreme temperatures and pressures while maintaining optimal viscosity.

Using a fluid that does not meet the Eaton PS-386 specification can lead to premature wear, difficulty shifting, reduced fuel economy, and potential transmission failure. Always ensure that any replacement fluid explicitly states compliance with or exceeds the Eaton PS-386 requirements.

Service Procedure

Servicing an Eaton heavy-duty transmission typically involves a drain and fill procedure. Unlike many passenger car transmissions, full fluid exchanges (flushing) are not commonly recommended or required for these units.

Drain & Fill Procedure (General Guidelines):

1. Preparation: Ensure the vehicle is on a level surface and the transmission fluid is at operating temperature to allow for better drainage. Have a suitable drain pan ready to catch the old fluid.
2. Drain: Locate the drain plug (usually at the bottom of the transmission case) and carefully remove it. Allow all the old fluid to drain completely. This can take some time due to the volume of fluid.
3. Inspect Drain Plug: Inspect the drain plug and its sealing washer. Replace the washer if damaged or if it