So I'm in the process of changing my tranny fluid but I am not seeing dex/merc lll which is recomended for my car. Valvoline has dex,/merc for cars with the use of 2 3 and 6. But Auto Zone didn't sell valvoline and I had already purchased castrol dex/merc but it says for use of 2005 and prior gm vehicles but not applications calling for dex Vl. I'm confused because valvoline says 2 3 &6 but castrol says don't use in cars with dex 6. My car says use dex 3 but ppl are telling me I need Vl but my tranny is a bit worn. Someone please help.