Quote Originally Posted by KX5062 View Post
MSJ's summary is right on the money, however, I might take issue with the marketing gimmick comment, but otherwise well put.
The fact that dot3, 4, and 5.1 fluids are all glycol based translates into the fact that they are all synthetic fluids. So when a manufacturer "takes advantage" of that fact and plasters a big bold "SYNTHETIC" label on their product to justify a higher price or to make you think it's better than a bottle next to it that isn't labeled so, kinda sounds like a gimmick to me, imho.