hi lads. i want to change the ATF in my 2009 accord 2,0. it has gone 77000km and have not been change ever by the looks of the service book. so the oil in the box is ATF-Z1 and the new oil i want to put in is ATF-DW1. just want to know if i have to flush the system 1,2 or 3 times or just tap the old and put the new in. can the new oil be mixed with the old or dosent ik work together.