2014 Peterbilt 389 Transmission Fluid & Service Spec

Quick Answer

• Transmission Make/Model: Eaton Fuller Advantage 10-speed Automated Manual Transmission (AMT) or Eaton Fuller RTOC-18909A 9-speed manual, depending on configuration. (Note: Many other Eaton Fuller models and Allison automatics were also available. Always verify your specific transmission.)
• OEM Fluid Spec: Eaton PS-386 (for Eaton Fuller Advantage AMTs) or Eaton PS-164 Rev 7 (for most manual Eaton Fuller transmissions). Always verify with your specific transmission service manual, as specs can vary significantly.
• Drain & Fill Capacity: Varies significantly by transmission model. For a typical Eaton Fuller Advantage AMT, expect 13-16 quarts. For manual transmissions, it can range from 15-20 quarts or more. Always refer to your service manual for exact capacities.
• Full Overhaul Capacity: Varies significantly, often 20-25% more than drain & fill due to fluid in coolers and lines. Always refer to your service manual for exact capacities.
• Filter OEM Part Number: No external filter for most Eaton Fuller transmissions. Internal screen may be present. Always verify with your specific transmission service manual.
• Recommended Service Interval:
  • Normal Duty (Eaton Fuller Advantage AMT): Up to 500,000 miles or 5 years, whichever comes first.
  • Severe Duty/Towing (Eaton Fuller Advantage AMT): 250,000-300,000 miles or 3 years, whichever comes first.
  • Normal Duty (Manual Eaton Fuller): Up to 500,000 miles or 5 years.
  • Severe Duty/Towing (Manual Eaton Fuller): 250,000 miles or 3 years. Always verify these intervals with your specific transmission service manual, as operational conditions and fluid analysis can alter recommendations.

Fluid Type Explained

The 2014 Peterbilt 389, being a heavy-duty truck, could be equipped with a variety of transmissions, primarily from Eaton Fuller. These transmissions are vastly different and require specific fluid specifications.

• Eaton Fuller Advantage Automated Manual Transmissions (AMTs): These modern AMTs often utilize a Synthetic Transmission Lubricant meeting Eaton PS-386 specification. This fluid is formulated for extended drain intervals, improved fuel economy, and enhanced component protection in automated applications. It's crucial to use the exact PS-386 spec fluid to ensure proper operation, shift quality, and longevity of the AMT