You can you DexronVI in any GM transmission that called for DexronIII.
I've also used it in place of T-IV, Mercon-V, D-matic, and non GM applications that require DexIII too, including power steering systems. I've been trying to create a non-OE fluid related failure and haven't yet.
Nice to know. I would be usin it in the 1999 Camry A541E transmission which calls for Dex III. As far as i know Dex VI is synthetic and probably would have a longer service life than Dex III. How is the Supertech Dex VI?
Dexron-VI is only backwards compatible in GM's Hydromatic tranmsissions. Most GM Allison transmissions that called for Dexron-III cannot use Dexron-VI...this the new name for old Dexron-III, Allison TES-389.
The requirements for Dexron-VI don't specify the type of base oil to be used, but the requirements are so tough that a synthetic blend or better is needed to pass the test.