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Transmission fluid really is liquid engineering. Castrol auto transmission fluid can restore smooth shifting, even in vehicles with over 75,000 miles on the odometer.

Engineered to exceed specifications

Automatic transmissions are now more complex than ever, placing ever-greater demands on auto transmission fluids.  In fact, the automatic transmission is perhaps the most complicated mechanical component in an automobile.  The automatic transmission combines electrical & mechanical systems, hydraulics and computer processors to smoothly shift through the gears and transfer engine power to the drive wheels. 


There are 3 basic types of automatic transmissions found throughout the world.  The Dual Clutch Transmission (or DCT), the Continuously Variable Transmission (or CVT) and the step-type transmission which is the most common, especially here in the US.  There are several main components that make up the step-type transmission.  The pump supplies pressurized transmission fluid for many uses throughout the unit.  The planetary gear sets provide the chosen gear ratios for the vehicle.  Clutches or “clutch packs” engage and disengage the gear sets.   The Torque Converter connects the transmission to the engine and multiplies the torque during initial acceleration.  It uses two turbines which spin independently, but which are fluid coupled allowing the engine to idle while the engine is stopped and produce smoother acceleration as it shifts through the gears. Finally, the Mechatronics is the “brain” of the transmission, a complex system of ports, valves and electronics that control all transmission functions. 


The one component of the entire system that’s critical to all of these parts working properly together is the Automatic Transmission Fluid, or ATF.  It acts as a hydraulic fluid, to engage clutch packs & shift the gears.  It acts as a corrosion inhibitor and wear protection for the Planetary Gear sets.  It has to flow easily from minus 40 degrees Fahrenheit to nearly 400, even in fine valve assemblies. The ATF precisely controls friction in the clutch packs and maintains it throughout the drain interval … which is perhaps the most important property of an ATF all while providing lubrication to hundreds of moving parts even under high temperatures and extreme pressure. So using the right ATF is critical to the performance and long life of your transmission.


The Castrol® Transmax portfolio contains a broad range of automatic transmission fluids liquid engineered to protect critical transmission components, including products that have been licensed by GM, Ford and Chrysler as well as fluids that meet the JASO requirements of popular Japanese imports from Toyota, Honda and Nissan.

Smooth Drive Technology™: Several Castrol Transmax products are formulated with Smooth Drive Technology™, which are active control molecules that automatically adjust their friction level under changing pressures and speed – delivering a smoother drive for longer.




Designed for use in the automatic transmissions of a wide range of cars, light commercial vehicles and SUVs except CVT. It can be used in GM, Ford, ZF and Aisan automatic transmissions vehicles requiring Dexron® III or Ford Mercon® fluids. Additionally it can be used in most Japanese vehicles requiring automatic transmissions fluid, Type IV fluid.