I just purchesed a used 2004 civic hybrid to commute for my new job. It does do a little bit of the Judder upon starting that sooooooo many people have experienced but since it is a know problem it does not worry me. But I would like to change the fluid because it was last changed about 30k ago and the manual says its time to change. In the manual it says to use ATF-Z1 fluid but I have found there is also a CVT fluid that honda puts out. Is it better to use the CVT fluid or should I stick with the ATF-Z1 that the manual says to use?