Mobil 1 is GL-5. Your tranny probably calls for GL-4. (I don't own a Civic). The difference is that GL-5 (In theory) corrodes yellow metals (brass and bronze). In actual practice GL-5's have improved to the extent that there is likely no problem. I would call the mobil hotline if the requirement is GL-4. If there is a problem you might want to replace it down the road. I really don't think its a big deal though in the short term.