This is super complicated. I did on mine 2012 ct200H (gen III Prius platform) at 62K miles, and it was a piece of cake. After WS fluid change, the CVT became more responsive and was a lot quieter. Located the filler bolt, cracked it open before draining it. It splashed little bit, and filled it up using a hand pump. I watched a Youtube whereas this guy drained his fluid only to find out that his filler bolt was "frozen shut" !!! PS: There was no dip stick for the transmission for my car.