Dexron VI—the newest GM ATF, it was developed specifically for the new six-speed automatic and is a synthetic blend (meaning it has some conventional base stocks). That transmission has tighter internal tolerances and required a fluid that had higher shear strength that Dexron III.
It was introduced with the 2006 models. GM considers Dexron VI to be "backward compatible," meaning GM recommends it for use in any vehicle that originally used any earlier version of Dexron and that it can be mixed with them. However, GM specifically recommends against using Dexron VI in non-GM made vehicles that used Dexron III as original equipment. It is also the specified ATF in certain non-GM models that use GM transmissions, such as BMW. It is not, however, specified for GM brand vehicles that have non-GM transmissions, as mentioned above, or are imported to the United States.
NOTE: Dexron VI is not recommended for: Pontiac Vibe and Wave, Chevy Aveo, Epica, and Equinox, Saturn ION with CVT or AF23 transmission, Saturn Vue with CVT, AF33 or 5AT transmissions, or 1991–2002 Saturn S. These are vehicles with transmissions that were not manufactured by General Motors.