I am more than likely over thinking this. But in my 2500 Avalanche with the 4L85E in it, what transmission fluid would be best to use? I have read Dex VI is a poor choice as these old transmission don't like it much, you can end up with torque converter issues? I read Maxlife or other universals are a good option, then others say it's not. It seems Dex IIIH is still produced, which I think is the closest available that came in it originally. In the end, just don't want to mess it up because I overlooked something. Fluid in it looks pretty nice and red, but I think the PO did dump and fills only and never changed the filter since it has a drain in the pan.