This is bogas I have been using dexron III with mercon for the past twenty years and have never had any problem with it on older cars about 96 mb changed to a steering fluid and i use the sweptco in the newer cars without any trouble (this fluid purges air out of fluid great)
dexron name is owned by gm and they have told every one they can not use their name any more so it has changed to domestic trans fluid for gm cars fluid spec is the same