Hello, I currently own a Prius 2010 with over 230,000 miles (and still going strong) on it and the transmission fluid has not been changed since. I am thinking about changing the transmission fluid even though normally we're not supposed to (Toyota normally expecting people to not use the car after 200,000 miles). I have found out that I need 3.5 quarts of fluid and that I need the genuine Toyota ATF-WS transmission fluid. However, I was wondering if it is okay to use alternatives that are pretty much compatible with the Prius engine and if so, what kind of third party transmission fluids could I use? I did a little research beforehand and someone suggested the Valvoline Maxlife as it is similar but I am not so sure. Thanks for your help guys!