I've had my is300 for over a year but this is my first post so be nice I was wondering how often do you need to change your transmission fluid? The dealer wanted to change it at 15k miles; however, the IS300 manual didn't support this. In fact, the dipstick for the transmission fluid has a "do not change" sticker around it. Any suggestions/help would be appreciated. BTW I have a '01 black/black with 23k pleasureable miles.