6 mos ago I bought a 2012 used RX 350 with high mileage. I am just curious after removing the orange level drain stick, the drained ATF is black and I got only about 750ml. Every time I drain and fill I got almost the same volume of atf drained. Is this normal? If it is not, what was wrong? The atf pan looked it has not been changed. Any ideas? Thanks.