The type of transmission fluid found in most Subaru vehicles is Dexron III and Dexron IV. However, some models have also used Subaru-rated transmission fluid.
Dexron automatic transmission fluid is available in four common weights, Dexron, Dexron II, Dexron III and Dexron VI. The numbers after each fluid are indicators to the succession of when each type was produced. As of 2015, Dexron III and Dexron VI are the most common types of fluid used inside of Subaru automatic transmissions.
Dexron VI was released in 2005. It has slightly less viscosity than its predecessors and allows the new transmissions to provide better power to the wheels, which helps improve the vehicle's fuel economy.