automatic transmission fluid flush & replacement

What does Automatic Transmission Fluid (ATF) do?

Automatic Transmission Fluid (ATF) provides the lubrication to the moving parts, wear and corrosion protection and is there to transfer the mechanical power of the automatic transmission. This is why regular servicing of an automatic transmission is vital to change this fluid (and its filter where fitted) in line with manufacturers recommendation. Failure to do this can result in many issues, such as transmission overheat, solenoid failure, jerky gear changes and even total gearbox failure.

What is an Automatic Transmission Fluid Flush?

A transmission fluid flush is a process in which the fluid in an automatic transmission is flushed out of the transmission (gearbox) and replaced with new Automatic Transmission Fluid (AFT). The flushing process, when done correctly, replaces nearly 100% of the old fluid with new fluid, including fluid in the torque converter and oil cooler lines.

How often should I have my automatic transmission fluid flushed?

Most manufacturers recommend replacing transmission fluid every 30,000 to 60,000 miles. If you tow anything, or do mostly city driving with more frequent changes of gears, it may be wise to change your ATF even more often.

What happens during an automatic transmission service?

There are many different processes required depending on the manufacturer, some of which may include all the following or just some:

• Mechanics will raise the vehicle and increase the gearbox temperature if required by the procedures.

• The gearbox drain plug will be removed, or a syphon pump inserted down the filler tube.

• If the vehicle has a filter, the sump is likely to be removed so the filter can be accessed.

• The parts will then be cleaned before a new filter is installed and the sump refitted with a new gasket or sealing compound.

• The gearbox will then be refilled with the correct ATF for the gearbox and application in accordance with the manufacturer's procedure.

• In some cases the refilling operation requires diagnostic input as well as manual.

• Once refilled to the correct level and run through its selection routine, the vehicle will be test driven before returning it to the owner.

What are the symptoms of requiring an Automatic Transmission Fluid Flush & replacement?

Usually, there a few signs you can look for:

• Transmission grinding or strange noises

• Problems changing or selecting Gears

• Slipping gears

• Failure to change up or down smoothly

• Jolts or a delay as you change from Park to Drive

• Transmission overheat warnings

• Transmission Control Unit warning lights