I have been reading up on automatic transmission fluid (ATF) lately and changes are on the horizon. Twenty years ago, there used to be just three types of ATF-one each for Ford, Chevy and Chrysler-and transmissions only had three speeds. Today, transmissions have up to six speeds, and run at higher temperatures for better efficiency. Most automatic transmissions have replaced mechanical parts with electronic solenoids, all with tighter clearances.
There are many more types of ATF to keep track of from manufacturer to manufacturer. It can get confusing, so a shop needs accurate information.
Incorrect fluid can cause shifting problems and premature wear. We are careful to use only OEM-supplied information to select the correct type of fluid for each particular vehicle. We also use either synthetic blends or full synthetic ATF, which are better than mineral-based fluids.
The main difference between types of transmission fluids is in the viscosity and additives. ATF must resist oxidation and thermal breakdown, and maintain the required viscosity levels at different temperatures. Viscosity applies to pancake syrup– if you heat it up, it pours easier. Transmission fluid has to resist getting too runny when hot, yet needs to flow when cold. The nice thing about synthetic ATF is the viscosity does not change much with temperature, so your transmission works better when cold and does not thin out when hot.
Transmission fluid does wear out, and when that happens it may have a catastrophic effect on your vehicle. Check my blog next week to find out if your car, truck or SUV is at risk.
Transmission fluid is kind of like pancake syrup–it must resist getting too runny when hot, yet flow smoothly when cold.