2005 mitsubishi galant 3.5 V6 transmission fluid help
 

I have a 2005 mitsubishi galant I bought from someone 3 months ago. I just checked the granny fluid and its brownish as you can see in the photo. I want to change it but i dont have a manuel. How much fluid does this transmission take? Also I will be using the official fluid from mitsubishi because i read on another forum not to use anything but. I also read that i dont need to change the filter on this car because the only way to get to it is by rebuilding the transmission. Correct me if I'm wrong please. Need to get this done asap