| Product Code | Package Size | Unit of Measure |
|---|---|---|
| FTF1G-EA | Gallon Jug | Each |
| FTF1G-CA | Gallon Jug | Case of 4 |
| FTF05-EA | 5 Gallon Pail | Each |
| FTF16-EA | 16 Gallon Keg | Each |
| FTF55-EA | 55 Gallon Drum | Each |
| FTF27-EA | 275 Gallon Tote | Each |
AMSOIL SAE 50 Long Life 100% Synthetic Transmission Oil delivers extended drain intervals of up to 500,000 miles in heavy-duty manual transmissions, cutting maintenance costs while providing superior wear protection for line-haul trucks and commercial equipment.
Manual transmissions in over-the-road trucks operate under constant high-torque loads, extreme temperature swings, and punishing schedules that break down conventional SAE 50 transmission fluids well before their drain interval is up. Viscosity shear, thermal degradation, and foam formation all accelerate wear on gears, bearings, and synchros. The cost of unscheduled downtime and premature rebuilds hits fleet operators hard, making fluid choice a real financial decision.
PROVEN 500,000-MILE WEAR PROTECTION
AMSOIL put this fluid to the test in real-world line-haul service, not just in a lab. After more than 500,000 miles, a transmission was pulled apart and inspected by a calibrated ASTM rater. The mainshaft gears and synchro friction material showed minimal wear across all critical components. The output seal did not leak and still retained 100 percent of its grease. Synthetic base oils resist viscosity loss due to mechanical shear far better than conventional fluids, maintaining a durable lubricating film under the high-load, high-torque conditions that Eaton Fuller and Mack transmissions see daily. In the 60-Hour KRL shear stability test (CEC L-45-A-99), this fluid showed only a -4.97% Vk100 loss, confirming its ability to hold viscosity over extreme service intervals.
YEAR-ROUND PERFORMANCE IN COLD AND HOT CONDITIONS
A viscosity index of 142 (ASTM D2270) means this synthetic SAE 50 transmission oil maintains consistent film strength at high temperatures while still flowing well in cold weather. At -40°C, Brookfield viscosity measures 117,483 cP (ASTM D2983), allowing drivers to shift smoothly in winter conditions without the stiff, sluggish gear engagement common with conventional fluids. Reduced fluid drag at low temperatures also contributes to improved fuel economy during cold starts and winter operation. At the other extreme, exceptional thermal stability resists chemical breakdown and sludge formation, keeping the transmission cleaner over hundreds of thousands of miles.
FOAM RESISTANCE FOR CONSISTENT GEAR PROTECTION
Churning gears constantly whip air into transmission fluid, creating foam. When foam bubbles collapse between loaded gear surfaces, the fluid film disappears and metal-to-metal contact takes over. AMSOIL Long Life Synthetic Transmission Oil scored 0/0, 0/0, 0/0 in ASTM D892 foam tendency testing across all three sequences. That means zero foam formation and zero residual foam at every test temperature, keeping a strong lubricating film on gear teeth and bearings at all times.
REDUCES MAINTENANCE COSTS AND DOWNTIME
A 500,000-mile drain interval versus the typical 50,000 to 100,000 miles of a conventional SAE 50 fluid translates directly to fewer oil changes, fewer hours in the shop, and more miles on the road generating revenue. For fleet operators running Kenworth, Peterbilt, Freightliner, or International trucks with Eaton Fuller or ZF Freedomline manual transmissions, the math is straightforward: fewer drain intervals over the life of the truck means lower total fluid cost, lower labor cost, and less waste oil to dispose of.
SEAL COMPATIBILITY
The formulation is designed to be compatible with transmission seals, helping prevent leaks and extend seal life over the full drain interval. The 500,000-mile teardown confirmed the output seal was still intact and performing as designed.
Specifications and Compatibility
AMSOIL SAE 50 Long Life Synthetic Transmission Oil is recommended for manual transmissions in heavy-duty equipment requiring an SAE 50 lubricant. It meets or is recommended for applications specifying:
Service Life
Follow the OEM drain interval for synthetic oil up to 500,000 miles or five years, whichever comes first.
| Property | Value | Test Method |
|---|---|---|
| Viscosity @ 100°C, cSt | 17.5 | ASTM D445 |
| Viscosity @ 40°C, cSt | 135.2 | ASTM D445 |
| Viscosity Index | 142 | ASTM D2270 |
| Specific Gravity (g/ml) | 0.8602 | ASTM D1298 |
| Density (lb/gal) | 7.16 | ASTM D1298 |
| Color | L4.0 (Red) | ASTM D1500 |
| Flash Point, °C (°F) | 226 (439) | ASTM D92 |
| Fire Point, °C (°F) | 254 (489) | ASTM D92 |
| Pour Point, °C (°F) | -42 (-44) | ASTM D97 |
| Four-Ball Wear Test, Para 1 (75°C, 1200 rpm, 40 kg, 1 hr) | 0.38 | ASTM D4172 |
| Brookfield Viscosity -40°C (cP) | 117,483 | ASTM D2983 |
| Foam Tendency | 0/0, 0/0, 0/0 | ASTM D892 |
| Copper Corrosion, 121°C, 3 hr | 1B | ASTM D130 |
| 60-Hour KRL (% Vk100 loss) | -4.97 | CEC L-45-A-99 |
What trucks and equipment use AMSOIL SAE 50 Long Life Synthetic Transmission Oil?
AMSOIL SAE 50 Long-Life Synthetic Transmission Oil (FTF) is designed for manual transmissions in high-torque, heavy-duty line-haul trucks and other commercial applications requiring an SAE 50 lubricant. It is recommended for applications specifying Eaton PS-164 Rev. 7, Navistar/International TMS 6816, Mack TO-A Plus, ZF Freedomline, Meritor 0-81, and Rockwell/Eaton/Fuller CD-50 (PS-081). Application categories include heavy-duty on-road, heavy-duty off-road, agriculture, auto/light truck, and various powersports equipment.
How does AMSOIL SAE 50 Long Life Synthetic Transmission Oil protect gears and bearings in heavy-duty trucks?
AMSOIL SAE 50 Long-Life Synthetic Transmission Oil uses synthetic base oils that withstand the pressures of high-load, high-torque applications, resisting viscosity loss due to mechanical shear to maintain a durable lubricating fluid film. AMSOIL conducted real-world testing by installing this oil in line-haul trucks, and after more than 500,000 miles a transmission was disassembled and inspected by a calibrated ASTM rater. Results confirmed outstanding wear protection in all critical components. The formula also contains foam inhibitors that prevent air bubbles from collapsing between gear surfaces, which would otherwise cause metal-to-metal contact and increased wear.
What specifications does AMSOIL SAE 50 Long Life Synthetic Transmission Oil meet?
AMSOIL SAE 50 Long-Life Synthetic Transmission Oil meets API GL-1 and MT-1 specifications. It is also recommended for applications specifying Eaton PS-164 Rev. 7, Navistar/International TMS 6816, Mack TO-A Plus, ZF Freedomline, Meritor 0-81, and Rockwell/Eaton/Fuller CD-50 (PS-081). The MT-1 specification is specifically designed for non-synchronized manual transmissions used in heavy-duty trucks and buses, ensuring the oil meets the unique demands of commercial transmission applications.
How does AMSOIL SAE 50 synthetic transmission oil compare to conventional transmission fluids in heavy-duty trucks?
Compared to conventional fluids, AMSOIL SAE 50 Long-Life Synthetic Transmission Oil offers superior high- and low-temperature performance thanks to its high viscosity index. In cold weather, it provides easier shifts and reduced fluid drag for increased fuel economy, while its exceptional thermal stability inhibits chemical breakdown and sludge formation at high operating temperatures to help transmissions run cleaner. Its ability to support drain intervals of up to 500,000 miles or five years can help operators significantly reduce maintenance costs and increase productivity versus conventional fluids that require more frequent changes.
How long can I go between oil changes with AMSOIL SAE 50 Long Life Synthetic Transmission Oil?
AMSOIL SAE 50 Long-Life Synthetic Transmission Oil supports drain intervals of up to 500,000 miles or five years, whichever comes first, following the OEM drain interval recommendation for synthetic oil. This extended service life was validated through real-world testing in line-haul trucks, where transmissions were disassembled after 500,000-plus miles and inspected by a calibrated ASTM rater, confirming outstanding wear protection in all critical components. This dramatically extended drain interval helps commercial operators reduce maintenance costs and vehicle downtime.
Is AMSOIL SAE 50 Long Life Synthetic Transmission Oil safe for transmission seals?
Yes, AMSOIL SAE 50 Long-Life Synthetic Transmission Oil is formulated to be compatible with transmission seals, helping prevent leaks and extend seal life. This seal-friendly formulation ensures that the oil will not degrade or shrink seals over time, which is particularly important for heavy-duty commercial transmissions that operate under sustained high temperatures and pressures. This compatibility helps operators avoid costly seal replacements and fluid loss throughout the extended drain interval.
Product Details PDF - AMSOIL SAE 50 LONG LIFE 100% SYNTHETIC TRANSMISSION OIL
