AMSOIL SAE 50 100% Synthetic Powershift Transmission Fluid

Product overview

AMSOIL SAE 50 Synthetic Powershift Transmission Fluid is the heaviest of the three powershift grades, specified where high loads and high operating temperatures call for the thickest film.

It also covers Rockwell, Eaton, Fuller, Spicer, Fabco, Warner, and other large truck manual transmissions, which makes it a dual-purpose fluid for mixed fleets running both equipment and highway trucks.

What the formula does

• Compatible with common metallic and non-metallic friction materials, with stable friction properties that help eliminate brake noise and vibration.
• Non-slip friction properties help prevent clutch slippage, which is what causes glazing and friction-surface deposits.
• Oxidation and thermal stability hold off varnish, deposits, and sludge, and the fluid doubles as a heat-transfer fluid to help cool hot-running equipment.
• Guards against copper corrosion and rust, even during storage, and it does not foam in service.

Where this fluid fits

Use in equipment such as:

• Dozers, wheel loaders, and crawlers
• Backhoe loaders and road graders
• Cranes and off-road fork trucks
• Harbor-handling and railway equipment
• Mining equipment
• Large truck manual transmissions
• Commercial marine applications

The heaviest grade for load, heat, and sustained torque

AMSOIL SAE 50 Synthetic Powershift Transmission Fluid measures 18.2 cSt at 100°C and 165.2 cSt at 40°C, the thickest of the three powershift grades, and it is the fill specified where loads and sump temperatures stay high. Equipment worked that hard puts sustained torque through the clutch packs, and the formula is built to hold its SAE 50 grade across the service life rather than thinning out under that load.

Cold weather is the trade-off. This grade pours at -36°C (-33°F), the highest pour point in the family, so machines that live outdoors through a hard winter are frequently written for Powershift SAE 30 or a lighter fill instead. The grade the equipment manufacturer specifies for the climate the machine actually works in is the one to buy.

Dual duty across equipment and highway trucks

Coverage on this grade reaches past powershift transmissions into large truck manual gearboxes from Rockwell, Eaton, Fuller, Spicer, Fabco, and Warner, and it is the only fluid in the powershift family carrying CD-50. For a mixed fleet running dozers and highway tractors out of one shop, that overlap can collapse two fluids into one, though the consolidation rests on the CD-50 listing rather than on the SAE 50 label by itself. The specification list on this page shows the full published coverage.

The 60,000-mile CD-50 interval

CD-50 manual transmission service runs to 60,000 miles or one year, whichever arrives first, unless the equipment manufacturer specifies something else. That figure belongs to this product in that application, and it is a different number from the long-drain program built around SAE 50 Long-Life Synthetic Transmission Oil. Matching the interval to the product actually in the sump avoids stretching a fill past what it was formulated to do.

Wear protection under sustained high torque

The formula meets the wear and frictional requirements of the Caterpillar TO-4 specification, and staying in grade throughout service life is what keeps that protection in place when equipment is frequently subjected to sustained high torque. In the four-ball wear test (ASTM D4172B at 40 kg, 75°C, 1200 rpm, one hour) it produced a 0.45 mm scar. The synthetic base oils and the heavy additive treatment behind that result were selected specifically for powershift transmissions.

Specifications Powershift SAE 50 covers

The SAE 50 grade covers applications requiring any of the following:

• Caterpillar TO-4
• Komatsu KES07.868.1
• Rockwell, Eaton, and Fuller CD-50

Coverage as published in the AMSOIL data bulletin, checked July 2026. AMSOIL revises coverage when a formula changes, so confirm against AMSOIL's current data bulletin before ordering.

Service life

The formula provides extended service life beyond conventional petroleum fluids as long as it stays free of dirt and moisture.

In CD-50 manual transmission applications it may be used up to 60,000 miles or one year, whichever comes first, or as specified by the equipment manufacturer.

Use oil analysis before extending service intervals beyond the equipment manufacturer's recommendation.

Good to know

• The powershift grades can be used in Caterpillar, Allison, Komatsu, Clark, Hurth, Borg-Warner, Twin Disc, Voith, ZF, Funk, and Brockhouse powershift-type transmissions, and in Eaton, Rockwell, and Fuller transmissions.
• Fully compatible with other TO-4 fluids used in powershift applications. To switch, drain the system, replace the filter if the equipment has one, and refill with the correct viscosity.

Typical technical properties

Typical properties published by AMSOIL, checked July 2026. These are representative values rather than a specification, and they change when AMSOIL updates a formula.

Package sizes and product codes

Select a product code to open that package size on the AMSOIL product page.

Product documents

AMSOIL publishes the full technical detail for this product in these documents.

• Powershift SAE 50 product data bulletin (PDF)
• Powershift SAE 50 safety data sheet (PDF)

Where to order

Confirm this formula is the match for the vehicle or equipment in the AMSOIL product guides, then order Powershift SAE 50 online. Existing members can sign in to apply the discount automatically.

Details and questions