subject: What is ATF and why should I change it? [print this page] What is ATF and why should I change it? What is ATF and why should I change it?
Automatic Transmission Fluid referred to as ATF is the fluid used in an automatic transmission. It is usually tinted red or green so that it does not get mixed up with other automobile fluids. It is usually checked with a dipstick while the engine is running. This special fluid meets all the requirements for gear lubrication, band friction, and valve operation. The automatic transmission depends on fluid to force friction plates to apply metal plates which will engage a series of gears to turn,
ATF may also be used as a lubricant for power steering pumps, manual transmissions, and transfer cases. Make sure you check your owner's manual to see what type of fluids you use in all applications.
There are different types of ATF that come standard in different motor vehicles and should not be interchanged or mixed. Again check the owner's manual to see if what type of fluids your vehicle uses.
For example, General Motors uses a fluid called DEXRON. In newer built vehicles, 2006 and up, transmissions require that you use DEX VI, where older vehicles use DEX III. You may use DEX VI in older vehicles, but do NOT use DEX III in place of DEX VI.
OEM formulas are based on synthetic stocks. Each vehicle maker has specific requirements and incorrect transmission fluid may result in severe damage or poor performance.
Current fluids types
ATF+4 - Most Dodge, Jeep, and Chrysler [1]
Mercon V - Most Ford, Mercury, Lincoln
Dexron VI - Most GM products, some Ford applications
ATF-Z1 - All Honda and Acura (except CVT)
Synthetic ATF is also available on the aftermarket if you require better performance for certain heavy duty applications such as towing.
You should check your transmission fluid with the engine running and a clean rag to wipe down the dipstick. (check your owner's manual for your specific instructions) If the fluid is dark brown or black, it may indicate that the fluid should be changed or that your transmission has a problem. If the transmission fluid is not changed, it will not provide intended lubrication properties and will generally reduce the life of the transmission.
When the first automatic transmission appeared it used an ATF which contained whale oil. Whale oil would break down at higher temperatures plus a moratorium on using whale oil prevented production. The vehicle manufacturers had to replace the fluid with new versions. General Motors, for example, switched to Dexron then moved to Dexron II, etc.
Whether you use the conventional fluid and filter change or the transmission flush which changes all the fluid instead of the few quarts that sit in the pan, this service should be done at least once a year or whatever your owner's manual suggests.
To purchase OEtransmission filters at aftermarker prices, try Saw Autmotive Parts Network.
