newer vehicles are sealed, the fluid intended for lifetime use in normal operation. Unlike motor oil Automatic Transmission Fluid (ATF) does not have to contend with byproducts of combustion, condensation or nasty gases. It simply lubricates and cools. A filter traps and renders microscopic gear particles harmless. Change ATF only if specified by the carmaker, or if it has been overheated or contaminated. There is a real risk a well intentioned ATF change will be bungled. Transmission fluid is strictly car make and model specific. It must adhere precisely to the automaker's formula. The manufacturer's branded ATF is best. Never put multivehicle ATF into your car. Chain stores and franchised repair, tire and quick lube shops are notorious for it. Correct fill level is critical. Transmissions are unforgiving of fill errors. Drive gently for several kilometers after a cold start so the transmission fluid reaches optimum operating temperature before it is stressed. Use the brakes to slow the car on long downhill runs, not the transmission. Change gears only when fully stopped. Never ??rock?_ a car out of snow, sand or mud. It will cook the ATF. A tow truck will be much less costly in the long run! Heat ruins ATF lubricity. If your car or truck is frequently heavily loaded, used as a tow vehicle or often driven in hilly country in hot weather install a good transmission cooler and change the ATF every 50,000 kilometers. "The automatic transmissions in many newer vehicles are sealed, the fluid intended