FS-ES SAE 40 Full-Synthetic Transmission Fluid – 20L
FS-ES SAE 40 Full-Synthetic Transmission Fluid – 20L
Fuel-efficient, full-synthetic SAE 40 lubricant for heavy-duty commercial manual transmissions requiring Eaton PS-386 performance.
TRANS FS-ES SAE 40 (Eaton PS-386) is a premium full-synthetic manual transmission fluid developed for heavy-duty commercial transmissions operating under extreme temperatures or extended service intervals. It combines excellent low-temperature performance with strong oxidation resistance and thermal stability, providing reliable year-round transmission protection.
The fluid is fully approved under the Eaton PS-386 specification and is suitable for extended-drain service in Eaton Roadranger® transmissions where this specification is required. The 20L pack is suitable for commercial vehicle workshops, transport operators and maintenance teams servicing compatible heavy-duty transmissions.
Why TRANS FS-ES SAE 40 Works
The full-synthetic formulation provides high shear stability, strong load-carrying capacity and effective anti-wear protection. These properties help protect synchronisers, reduce component wear and minimise gear micropitting in demanding manual transmission applications.
Its low-temperature fluidity supports easier shifting in cold weather, while its oxidation resistance and thermal stability help maintain lubricant performance at elevated operating temperatures. The product data sheet reports fuel-efficiency improvements of up to 1.5% compared with previous-generation SAE 50 manual transmission fluids.
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Details
- Product type: Full-synthetic heavy-duty manual transmission fluid
- SAE grade: SAE 40
- Performance classification: API MT-1
- Primary approval: Eaton PS-386
- Pack size: 20L
- Appearance: Amber
Key Benefits
- Extended-drain performance for approved heavy-duty transmission applications
- All-season protection across a wide range of operating temperatures
- Outstanding oxidation resistance and thermal stability
- Improved low-temperature properties for easier cold-weather shifting
- High shear stability helps maintain lubricant performance in demanding service
- High load-carrying capacity for higher-torque transmission applications
- Anti-wear protection for synchronisers and transmission components
- Protection against gear micropitting, rust and corrosion
- Good foam resistance supports consistent lubrication
- Excellent seal compatibility
Recommended Applications
TRANS FS-ES SAE 40 is designed for heavy-duty manual and semi-automatic transmissions in commercial vehicles where the equipment manufacturer specifies one of the following lubricant types:
- A non-EP SAE 40 or SAE 50 API MT-1 transmission fluid
- An API GL-1 SAE 90 gear oil
- An SAE 40 or SAE 50 heavy-duty engine oil for the transmission
- An Eaton PS-386-approved service-fill lubricant
It is particularly recommended for newer, higher-torque manual transmissions paired with increased-horsepower engines, provided the transmission manufacturer specifies the relevant performance standard.
Extended-Drain Service
TRANS FS-ES SAE 40 is approved under Eaton PS-386, which supersedes Eaton PS-164 Revision 7. The product data sheet states that the fluid is approved for extended-drain service of up to 500,000 miles in line-haul operation in compatible Eaton Roadranger® transmissions.
Actual drain intervals must always be determined by the equipment manufacturer's maintenance requirements, operating conditions and oil-monitoring recommendations.
Specifications and Approvals
- Eaton PS-386: Approved for service fill
- API Service MT-1: Meets or exceeds requirements
- Navistar MPAPS TMS 6816: Meets or exceeds requirements
- Mack TO-A Plus: Meets or exceeds requirements
- Meritor O-81: Meets or exceeds requirements
Typical Properties
- SAE grade: 40
- Colour: Amber
- Flash point, COC: 238°C
- Pour point: -42°C
- Brookfield viscosity at -40°C: 51,900 cP
- Kinematic viscosity at 40°C: 95.1 cSt
- Kinematic viscosity at 100°C: 14.8 cSt
- Viscosity index: 163
Note: Typical property values are averages and do not constitute a product specification. Minor manufacturing variations may occur.
Choosing the Correct Transmission Fluid
Before purchasing, confirm that the transmission manufacturer specifies Eaton PS-386, API MT-1 or another performance requirement listed above. Do not select a transmission lubricant based only on viscosity grade, vehicle type or operating industry.
Always consult the vehicle or transmission handbook for the required lubricant specification, viscosity grade and approved service interval. Using an unsuitable fluid may affect shifting performance, component protection, drain intervals or warranty requirements.
