AMSOIL SAE 50 Long Life 100% Synthetic Transmission Oil

Specifically Engineered for 500,000-Mile Service in Over-The-Road Trucks

  • Maximizes gear and bearing life
  • Helps operators save money
  • Promotes smooth shifts
  • Helps extend seal life and prevent leaks

Product Overview

AMSOIL SAE 50 Long-Life Synthetic Transmission Oil is specially formulated to meet the demanding requirements of manual transmissions found in high-torque, heavy-duty line-haul trucks and other commercial applications. Its synthetic base oils and premium additives help reduce wear (see photos), improve shifting and extend transmission life throughout drain intervals of up to 500,000 miles/five years. Compared to conventional fluids, Long-Life Synthetic Transmission Oil can help operators reduce maintenance costs and increase productivity.

Resists Wear
AMSOIL Long-Life Synthetic Transmission oil’s synthetic base oils withstand the pressures of high-load, high-torque applications. As a result, it resists viscosity loss due to mechanical shear to provide a durable lubricating fluid film for increased wear resistance and longer transmission life.

To prove its effectiveness, AMSOIL installed SAE 50 Long-Life Synthetic Transmission Oil in line-haul trucks and placed them into real-world service. After more than 500,000 miles, a transmission was disassembled and inspected by a calibrated ASTM rater. Results reveal Long-Life Synthetic Transmission Oil provided outstanding wear protection in all critical components (see images).

Year-Round Performance
AMSOIL Long-Life Synthetic Transmission oil’s high viscosity index translates into better high- and low-temperature performance compared to conventional fluids. In cold weather, it provides easier shifts and reduced fluid drag for increased fuel economy. Its exceptional thermal stability inhibits chemical breakdown and sludge formation at high operating temperatures to help transmissions run cleaner.

Inhibits Foam
Churning gears introduce air into the fluid, causing foam. When bubbles between gear surfaces collapse, metal-to-metal contact and increased wear result. Long-Life Synthetic Transmission Oil contains foam inhibitors to ensure formation of a strong lubricating film and excellent wear protection.

Seal Friendly
Long-Life Synthetic Transmission Oil is compatible with seals to help prevent leaks and extend seal life.

Applications
AMSOIL SAE 50 Long-Life Synthetic Transmission Oil is excellent for use in manual transmissions requiring an SAE 50 lubricant found in heavy-duty equipment. It is recommended for applications specifying any of the following:

  • Eaton* PS-164 Rev. 7
  • API GL-1 and MT-1
  • Navistar*/International* TMS 6816
  • Mack* TO-A Plus
  • ZF* Freedomline
  • Meritor* 0-81
  • Rockwell*/Eaton/Fuller* CD-50 (PS-081)

Service Life
Follow the OEM drain interval for synthetic oil up to 500,000 miles or five years, whichever comes first.

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Product information checked: September 2026. Product formulations, specifications, applications, availability and published claims can change.
For the latest official information, consult the AMSOIL Corproate Website.

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