Castrol Transmax ATF+4 is a technologically advanced, full synthetic automatic transmission fluid designed for superior transmission life and superb low and high temperature performance. Commonly called ATF4, it is certifi Castrol Transmax ATF+4 is a technologically advanced, full synthetic automatic transmission fluid designed for superior transmission life and superb low and high temperature performance. Commonly called ATF4, it is certified for use in all Fiat Chrysler cars and trucks (License Number: 40630033) that require ATF+4, ATF+3 or a previous Chrysler transmission specification such as ATF+2, ATF+2 Type 7176, or ATF+.