to 35,000-mile range. New technologies allow for a complete transmission flush.
Old fluid is flushed out and new fluid is pumped in. When performing a
complete flush, always replace the filter to ensure that all the dirt has been
removed.
Caution: Flushing fluid on transmissions that have been neglected for a long
time can result in internal damage. This topic is discussed in the chapter on
transmissions and drivetrains.
Air and Fuel Filters
Engines are managed by computers. The engine control module (ECM) directs
air-fuel mixtures, fuel pressure, and fuel delivery. It collects data from sensors
located throughout the engine, analyzes the data, and sends out engine
commands. When an air filter or a fuel filter gets clogged up, things go haywire.
Fuel delivery systems make wild adjustments within their operating parameters
in order to correct the malfunction of the performance system. This response
causes poor drivability, lowers the fuel mileage, and decreases overall
performance. That’s why it’s so important to keep fuel and air filters changed as
per manufacturers’ recommendations. Rule of thumb: fuel filter replacement
every two years or 20,000 miles, whichever comes first; air filter replacement
every 12 months or 10,000 to 15,000 miles, whichever comes first. Check your
owner’s manual to see what your carmaker recommends.