AMSOIL Synthetic Powershift Transmission Fluid is specifically designed for high-torque, heavy-duty powershift transmissions. Formulated for extended drain intervals, Powershift Transmission Fluid contains top-quality synthetic base oils and a high level of top-quality additives selected specifically for powershift transmissions. It offers exceptional transmission friction performance, smooth brake operation, gear and bearing wear protection and maximum equipment life.
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Product data sheets
View, download, or save a copy of the Product Data Sheet or Safety Data Sheet for AMSOIL SAE 50 100% Synthetic Powershift Transmission Fluid.
AMSOIL SAE 50 100% Synthetic Powershift Transmission Fluid (CTL) is the heavy-viscosity grade in the Powershift family, formulated for high-torque, heavy-duty powershift transmissions, wet brakes, final drives, and large truck manual transmissions running in hot climates and sustained load. Built on synthetic base oils with a heavy dose of premium additives, the SAE 50 grade is targeted at fleet, mining, quarry, marine, and tropical heavy-equipment operators who need a Caterpillar TO-4 fluid that holds grade under sustained high torque and high temperature.
Caterpillar TO-4, Komatsu KES, and CD-50 performance
The SAE 50 grade meets the wear and frictional requirements of the Caterpillar TO-4 specification and is also recommended for Komatsu KES 07.868.1 and Rockwell, Eaton, and Fuller CD-50 service. Stable frictional characteristics support smooth power transmission through clutches and synchronizers, smooth wet-brake operation, and superior hydraulic fluid performance, which matters in single-sump powershift designs that share fluid between the transmission, brakes, and final drives.
Clutch slippage and brake-noise control
Synthetic Powershift Transmission Fluid is compatible with common metallic and non-metallic friction materials. Stable frictional properties help eliminate excessive brake noise and vibration in oil-cooled wet brakes. Non-slip friction characteristics are designed to prevent clutch slippage, the root cause of glazing, friction-surface deposits, and material degradation that shorten clutch pack life in dozers, loaders, and articulated equipment.
Shear stability and wear protection under sustained high torque
Sustained high-torque service in mining, quarry, dozer, and timber operations shears conventional fluids out of grade. The SAE 50 formula is engineered for superior shear stability so the fluid stays in grade throughout its service life, providing long-term protection against gear and bearing wear even when equipment is frequently lugged at full load. Four-Ball Wear Test results (ASTM D4172B at 40 kg, 75 C, 1,200 rpm, 1 hr) record a 0.45 mm wear scar for the SAE 50 grade.
High-temperature stability for hot-climate and tropical service
In high temperatures, AMSOIL Synthetic Powershift Transmission Fluid effectively protects components from wear. Superior oxidative and thermal stability inhibit the formation of varnish, deposits, and sludge so equipment runs clean. The fluid also functions as a heat-transfer medium and helps cool hot-running equipment, an advantage in tropical operations and heat-soaked single-sump powershifts. Flash point reaches 224 C (435 F) and fire point reaches 246 C (475 F) per ASTM D92.
Cold-temperature flow, copper corrosion, and foam control
In cold temperatures, the SAE 50 grade flows readily for dependable startup and post-startup protection, with a pour point of -36 C (-33 F) per ASTM D97. The formula protects equipment from copper corrosion and rust, even during seasonal storage, and resists foaming in service to maintain a continuous oil film between metal surfaces under shock loads.
Recommended applications and service intervals
AMSOIL SAE 50 (CTL) Synthetic Powershift Transmission Fluid is recommended for applications and equipment that require any of the following:
Caterpillar TO-4, Komatsu KES 07.868.1, and Rockwell, Eaton, Fuller CD-50.
Powershift-type transmissions, final drives, and wet brakes in Caterpillar, Komatsu, Clark, Hurth, Borg-Warner, Twin Disc, Voith, ZF, Funk, and Brockhouse equipment, along with Eaton, Rockwell, and Fuller transmissions, where the OEM specifies an SAE 50 TO-4 fluid.
Large-truck manual transmissions specifying CD-50, including Rockwell, Eaton, Fuller, Spicer, Fabco, and Warner gearboxes, plus dozers, wheel loaders and crawlers, backhoe loaders, cranes, off-road fork trucks, harbor-handling, railway, mining, road graders, and commercial marine applications.
The SAE 50 grade is not approved for Allison C-4, Dana powershift, or ZF TE-ML 03C service. Those approvals are carried by the SAE 10W (CTG) and SAE 30 (CTJ) grades; check the AMSOIL vehicle lookup guide when matching the right viscosity to a specific machine.
For CD-50 manual transmission applications, the SAE 50 grade may be used up to 60,000 miles or one year, whichever comes first, or the interval specified by the OEM. Service life beyond conventional petroleum fluids depends on keeping the fluid free of dirt and moisture, and oil analysis is recommended when extending service intervals beyond equipment manufacturer recommendations. Synthetic Powershift Transmission Fluid is fully compatible with other TO-4 fluids used in powershift applications, although mixing reduces the performance benefit of a full synthetic fill. Aftermarket additives are not recommended.
Typical technical properties
Property
Value
SAE viscosity grade
50
Kinematic viscosity at 100 C, cSt (ASTM D445)
18.2
Kinematic viscosity at 40 C, cSt (ASTM D445)
165.2
Viscosity index (ASTM D2270)
123
Flash point, C (F) (ASTM D92)
224 (435)
Fire point, C (F) (ASTM D92)
246 (475)
Pour point, C (F) (ASTM D97)
-36 (-33)
Four-Ball Wear Test scar, mm (ASTM D4172B at 40 kg, 75 C, 1,200 rpm, 1 hr)
0.45
Order AMSOIL SAE 50 100% Synthetic Powershift Transmission Fluid
AMSOIL SAE 50 100% Synthetic Powershift Transmission Fluid is available in 5 Gallon Pail (CTL05-EA), 55 Gallon Drum (CTL55-EA), and 275 Gallon Tote (CTL27-EA). All AMSOIL products are backed by the AMSOIL Limited Warranty. Confirm the right viscosity and TO-4 grade for the machine using the AMSOIL vehicle lookup guide and review the broader transmission fluid lineup in the AMSOIL ATF guide before placing an order. Order Now.
I have been using this product in the rear end of my 1971 Flextrack Nodwell snow cat for over ten years. It performs well with wet brakes and keeps the gear box well protected and cool.
By Aj from Jackson hole on January 29, 2026.
Would recommend this to a friend.
Best transmission in oil by far.
I use this in all of our manual transmissions and so far I like what see smoother shifts. The guys are very hard on the trucks so I want the best in them.
By John from Marlboro nj on June 23, 2025.
Would recommend this to a friend.
Never disappoints
Was doing a clutch on a Eaton 13 speed and decided to replace the oil not knowing the status of the oil that was in the transmission. Oil looked fine but replaced anyway and so glad I did because it actually shifts so much smoother now. I love amsoil products and they will never let you down!
What is Caterpillar TO-4 and why does it matter for powershift transmissions?
Caterpillar TO-4 is a frictional and wear performance specification developed for powershift transmissions, wet brakes, and final drives. It controls the static and dynamic friction profile of the fluid so oil-cooled clutches engage smoothly without slipping or chattering, and so wet brakes do not squeal or grab. AMSOIL SAE 50 100% Synthetic Powershift Transmission Fluid meets the wear and frictional requirements of the Caterpillar TO-4 specification in the SAE 50 viscosity grade.
When should the SAE 50 grade be chosen instead of SAE 30 or 10W?
The SAE 50 grade is the hot-climate, high-load choice for powershift transmissions and CD-50 manual gearboxes operating at sustained high temperature, in tropical regions, in heavy mining and quarry duty, and in large truck manual transmissions where the OEM calls for an SAE 50 TO-4 fluid. SAE 30 and 10W cover lighter-duty service or colder ambient temperatures. The owner manual or OEM service bulletin specifies which TO-4 viscosity is approved for a given machine and ambient range.
Can the SAE 50 grade be used in Allison C-4 or ZF TE-ML 03C transmissions?
No. The SAE 50 grade carries Caterpillar TO-4, Komatsu KES 07.868.1, and Rockwell, Eaton, Fuller CD-50 approvals. Allison C-4, Dana powershift, and ZF TE-ML 03C approvals are carried by the SAE 10W (CTG) and SAE 30 (CTJ) grades in this family, not the SAE 50. Always match the OEM-specified viscosity and approval to the machine.
Is this fluid compatible with the conventional TO-4 fluid already in the transmission?
Synthetic Powershift Transmission Fluid is fully compatible with other TO-4 fluids used in powershift applications. Top-off mixing will not damage the system. To capture the full performance benefit of a synthetic fill, drain the existing fluid, replace the filter where equipped, and refill with the appropriate viscosity of AMSOIL Synthetic Powershift Transmission Fluid.
How long can the SAE 50 grade run between drains in a CD-50 manual transmission?
In CD-50 manual transmission applications, the SAE 50 grade may be used up to 60,000 miles or one year, whichever comes first, or the interval specified by the OEM. Powershift transmissions, wet brakes, and final drives should follow the equipment manufacturer drain interval, and oil analysis is recommended when extending intervals beyond OEM recommendations.
Will this fluid handle hot-climate and tropical heavy-equipment service?
Yes. Superior oxidative and thermal stability inhibit the formation of varnish, deposits, and sludge under sustained high temperature, and the fluid functions as a heat-transfer medium that helps cool hot-running equipment. The SAE 50 viscosity is the heaviest grade in the Powershift family and is the typical choice for tropical climates, mining, quarry, harbor-handling, and other heat-soaked operations.
Are aftermarket transmission additives recommended with this fluid?
No. AMSOIL SAE 50 100% Synthetic Powershift Transmission Fluid is fully formulated for TO-4, Komatsu KES, and CD-50 service, including frictional balance, anti-wear chemistry, copper-corrosion inhibitors, and foam control. Aftermarket additives can disrupt the friction profile and are not recommended.
