Why specially adapted ATF oils are important
Increasing demands on ever better fuel economy and lower greenhouse gas emissions are calling for more and more complex vehicle constructions. For automatic transmission vehicles, technical developments mean it’s more important than ever to choose the right ATF (Automatic Transmission Fluid) product, to ensure the transmission works optimally its entire life.
Never have there been as many different types of transmission as in today’s vehicles. Today the focus is increasingly on the transmission working with the rest of the vehicle to provide better overall performance with greater fuel efficiency, lower emissions and a more comfortable driving experience.
Automatic transmissions contain many components made of different materials, and they all have to work smoothly and reliably together. These include torque converters, planetary gearsets, the centrifugal oil pump, seals, and clutch and brake sets.
There is a trend towards more gears, while alternative, often lighter, materials are used. This is placing ever higher demands on the ATFs, which are vital to transmission function.
An ATF is probably the most complex of all lubrication fluids.
The oil has to both cool and lubricate, while also transmitting power and pressure. The requirements an ATF has to meet may seem contradictory. For example it has to reduce friction and reduce wear on components, while also providing a carefully balanced friction level that enables the clutch and torque converters to work efficiently. ATFs must increasingly also last the entire life of the system without changing, have high anti-friction strength, good shear stability, be fluid at low temperatures and offer better oxidation stability. All of these requirements have to be met. Meanwhile the oil should help to boost fuel efficiency and reduce emissions in co-operation with each specific transmission solution.
Since the hardware constructions in the automotive industry are becoming increasingly complex, it is no wonder that demands are being placed on the fluids that exclude universal solutions, for both new and old vehicles with automatic transmission.
Costly failures or problem-free operation
Potential consequences of using fluids that have not been specially developed and tested for the automatic transmission in question are poorer acceleration, difficulty changing gear, excessive wear on components, and in the worst cases a total (and very expensive) gearbox breakdown. Some types of damage will not be immediately noticeable after changing oil, but will become evident down the line.
On the other hand, the advantages of using the right, specially adapted ATF are considerable, including a lower cost of ownership, reduced service requirement and lower maintenance costs, greater operational reliability, higher fuel efficiency and a better driving experience.
A complex process
Development and validation of ATFs are a complex process due to the wide range of performance requirements and the many different materials used in the components. OEM-specific tests and industry standard tests must be carried out to validate the ATF performance, before final long-term testing of durability in transmissions and vehicles.
Tested, approved ATF oils with the right composition contain a balanced mixture of base fluid, performance-enhancing additives and viscosity modifiers, all of which serve important, very specific purposes. Important performance-enhancing additives in ATFs include friction modifiers, detergents and dispergents, foam, oxidation and corrosion inhibitors, pour point depressants, seal-swell and anti-wear additives.
The contents of all these additives must be carefully balanced to ensure they work together and perform their specific functions. Specialist chemists create the complex compositions to ensure that the additives, base fluid and viscosity modifiers do not work against each other, so the ATF can work in the intended way with the automatic transmission’s mechanical parts.
The comprehensive development and testing process guarantees the specially adapted ATF’s function in the transmission for the whole life of the vehicle.