The vast majority of passenger car and light truck transmissions operate automatically, that is without the need to manually shift gears. Automatic transmission fluid is a critical component of any automatic transmission. Also referred to as ATF, this fluid ensures proper operation, performance and protection of the automatic transmission. Critical areas of performance include the following:
Depending upon your vehicle manufacturer, model type, and model year, a specific automatic transmission fluid will be required to ensure proper transmission performance and protection. Always follow the recommendation of the vehicle manufacturer to ensure the proper fluid is used and fluid change interval is maintained. This recommendation can commonly be found in your vehicle owner’s manual.
The types of Automatic Transmission Fluids fall into a few categories:
1). Ford, GM and Chrysler ATF specifications:
ATF Fluids are not defined by a weight as is motor oil. Rather it is defined by specification, certification or application.
Ford, GM, and Chrysler have established their own specifications for automatic transmission fluids. For GM it is the DEXRON series of specifications with the mainstream specification being DEXRON VI for newer GM vehicles. Earlier DEXRON specifications would be acceptable for older GM vehicles. For Ford, the MERCON
specification is important with the latest being MERCON LV. For Chrysler the ATF +4 specification is the latest specification.
2). Multi-Vehicle Transmissions ATF
Multi-vehicle transmission fluids have become popular and these may carry GM, Ford and Chrysler certifications but also be suitable for use in Japanese and European vehicles.
3). Continuously Variable Transmissions (CVTs)
CVTs are growing in usage to improve fuel economy. Such transmissions are common to hybrid vehicles but can be found on non-hybrids as well. CVT transmissions have continuously changing speed ratios unlike classic automatic transmissions, also known as “step transmissions,” which have distinct gear shifts. A CVT fluid should be used in this application to ensure proper performance and protection especially with the CVT push belt regarding wear protection.
4). Type F Transmission Fluid
This fluid meets old Ford specification and is not commonly recommended for today’s transmissions. This may be the fluid of choice of older Ford classic cars, racing or hydraulic applications.
The proper time to change automatic transmission fluid will be defined in individual owner’s manuals. In many cases fluid change interval requirements will be more frequent if the vehicle is operated under severe conditions. Such conditions will be defined by the manufacturer.