2017 Peterbilt 579 Transmission Fluid & Service Guide

Quick Answer

• Transmission Make/Model: Eaton Fuller Advantage Automated Manual Transmission (AMT) or Eaton Fuller UltraShift PLUS AMT (depending on exact build)
• OEM Fluid Spec: Eaton PS-386
• Drain & Fill Capacity: Approximately 13-16 quarts (depending on model and cooler size - verify with service manual)
• Full Overhaul Capacity: Approximately 17-20 quarts (depending on model and cooler size - verify with service manual)
• Filter OEM Part Number: No external replaceable filter for most Eaton Fuller automated manual transmissions. Internal filters are typically non-serviceable during routine maintenance.
• Recommended Service Interval: 250,000 miles or 3 years, whichever comes first (normal duty); 125,000 miles or 1.5 years (severe duty / sustained heavy hauling / mountainous terrain).

Fluid Type Explained

For the 2017 Peterbilt 579, the most common transmission found will be an Eaton Fuller Automated Manual Transmission (AMT), either from the Advantage or UltraShift PLUS series. These transmissions do not use traditional Automatic Transmission Fluid (ATF). Instead, they require a specialized heavy-duty transmission lubricant. The OEM fluid specification for these Eaton transmissions is Eaton PS-386. This is a synthetic blend or full synthetic lubricant designed to provide optimal protection, fuel efficiency, and extended drain intervals for Eaton's automated manual transmissions.

Using a fluid that does not meet the Eaton PS-386 specification can lead to premature wear, shifting issues, reduced fuel economy, and potential transmission failure. Always consult your owner's manual or the Eaton service manual for the most precise fluid requirements for your specific transmission model.

Service Procedure

Servicing an Eaton Fuller AMT primarily involves draining and refilling the transmission fluid. Unlike many automatic transmissions, these AMTs generally do not have an external, easily replaceable fluid filter during routine maintenance. Internal filtration exists, but it's usually part of the transmission's internal components and not a separately serviced item.

Drain & Fill: This is the standard service procedure. It involves draining the old fluid from the transmission case and refilling it with new, specified fluid. Due to the design of these transmissions, a complete fluid exchange (like a flush) is not typically performed or recommended in the same way it would be for a conventional automatic. The drain and fill process effectively replaces the majority of the working fluid.

Capacity: The drain and fill capacity for a 2017 Peterbilt 579 with an Eaton Fuller AMT typically ranges from 13-16 quarts. Full overhaul capacity, which would involve completely dry components, can be closer to 17-20 quarts. It