Tips for your vehicle's automatic transmission

Automatic transmissions have made operating a motor vehicle safe and more convenient. Drivers no longer need to struggle through gear changes common in “manual” transmissions.
Yet, “automatic” does not mean “maintenance free.” How can you help keep your vehicle’s automatic transmission operating properly and prevent expensive breakdowns?
“Most people never think about their automatic transmissions as long as they are operating properly,” said Tony Molla, vice president of communications at the National Institute for Automotive Service Excellence. “Transmissions have a lot of moving parts and need routine maintenance, just like a vehicle motor.”
Automatic transmissions were first mass-produced in the 1930s and became commonplace on American vehicles during the 1950s. The shift from manual transmissions accelerated the variety of fluids used to keep the complex systems operating properly.
Fluid used in an automatic transmission contains a combination of oil and additives such oxidation compounds, high-temperature thickeners and rust preventatives. Manufacturers design the fluid for specific transmissions and applications.
For instance, trucks require fluid that can dissipate heat cause by heavy loads or towing. Passenger vehicles may need fluid that runs properly as high speed.
“The main job of transmission fluid is to dissipate heat inside gear mechanisms,” Molla said. “Old fluid breaks down and loses some of its ability to remove heat. That shortens the life of an automatic transmission.”
Transmission fluid also plays an integral role in lubricating parts. Friction inside the gear case leaves behind metal shavings the must be removed to prevent corrosion and wear.
“Metallic particles increase wear and clog transmission filters,” Molla said. “Old fluid also loses its ability to remove these particles from the intricate gear mechanisms.”
How do you help extend the life of your automatic transmission? Molla had the follow suggestions:
  • Perform an automatic transmission fluid replacement regularly. Check with your service advisor on manufacturer recommended intervals. They vary greatly by vehicle and driving habits.
  • Use manufacturer-recommended automatic transmission fluid. Oil and additives that make up the fluid are designed for specific types of transmissions.
  • Exchange the transmission filter when replacing transmission fluid. Metal shavings in an old filter can contaminate the system.
  • Consider how you operate your vehicle. Towing heavy loads in hot environments can break down fluid faster than light loads in mild weather. Ask your service advisor if you need a supplemental transmission cooler if you use your vehicle for towing.
“Heat destroys the additive packages manufacturers include in transmission fluids,” Molla said. “You can get the best performance out of your automatic transmission through regular fluid replacement and avoid problems when traveling away from home.”