Many standard automatic transmission motor vehicles and/or heavier duty vehicles like earth movers utilize fluid coupling type torque convertors. This is where the fluid forms a hydraulic function in separating the input power from the output power. Since the hydraulic fluid is circulating within an assembly containing moving parts that need lubrication a hydraulic fluid that can also be a lubricant is desirable.
Automatic Transmission Fluid (ATF)
ATF is the fluid used in most modern automatic transmission systems. It is typically red or green in color to distinguish it from other oils or fluids used in the same vehicle. As well as acting as a hydraulic fluid, the ATF will also be lubricating and cooling the insides of the transmission system. There are several different specifications for these fluids. Usually, these are drawn up by a vehicle manufacturer and customized to suit the results that are desired for that particular maker’s particular function. An off-road heavy duty dump truck will have different power (torque) requirements from (say) a high-performance street car, racing car, or dragster.
In use, the fluid could become slightly oxidized by local heat build from friction, etc, or, it could be contaminated by small particles that have worn or broken off other components (especially dust from friction materials). For efficient operation, it is important that the fluid be kept clean and for this reason, many vehicles (especially high performance or heavy duty ones) will be fitted with a transmission fluid filter.
Transmission Fluid Filters
Whereas normal engine oil filters for most motor cars are a cartridge design that can be screwed into the side of the engine block, a Transmission Fluid Filter will normally be found inside the oil pan type reservoir (sump) below the transmission unit. Thus replacing the ATF filter will require draining and opening the oil pan. Since this is not a quick fit job like topping up the reservoir or even a quick change over for the cartridge inside a engine oil filter, it is in everyone’s best interest that these ATF filters not only be efficient but also have a long life capability. To achieve this end, their designers have to consider all aspects of the fluid to be filtered as well as the function that the fluid serves in the automatic transmission system.
Raybestos Powertrain, LLC are probably the world’s longest serving experts in automotive friction materials – especially those associated with automatic transmissions. Over the years, they have enlarged their interest to include most component parts for transmission systems which is why they now have a transmission fluid filter on their product range.
