mizzouguy
Full Access Member
Gm switched from dex-iii to dex-vi (synthetic) in 06 roughly. Older vehicles were all super-ceded to the newer "better" fluid. I used to use dex-iii on my 04 because it was the factory fill back then, and it is what MY owners manual specifies. Like someone else said, you can top off older vehicles with the newer fluid (says gm), but you don't wanna put dex-iii in a newer vehicle. When I switched out all of the fluid when I did my filter and fluid change, I went with dex-vi at that point.
