Automatic Transmission flush or drain?
Hey people; I have a 1997 D90 automatic with 82000 km. Low, I know, but I'd like to change over to Amsoil synthetic. Should I flush or drain? I realize a lot of oil stays put from a draining but aside that...is there any concerns about flushing these auto transmissions? Of course I have a new filter/screen ready to go. Thanks for any input!