I just did a 50% service in my clean CRV trans that was full of Z1 with 2q of MaxLife and 1q of Mobil 1 ATF. It shifts smooth. My notion is that you should not use a run-of-the-mill Dex, but a premuim one is ok. Universal ATF is a plus, but finding one in synth is questionable. Noone has mentioned the Pennzoil products...they are worth looking at, but MaxLife "recommends" for Z1 and my unit is a 98 with 95k. I will service it again with the same mix. I am a lil crazy, I guess.