Introducing the latest formulation of Castrol TranSynd 668 Allison, now updated to meet the 2021 specifications. Packaged in a case of 3 by DOXA Worldwide, this high-performance transmission fluid is designed specifically for Allison transmissions to deliver unparalleled performance and reliability. Delivers improved gear protection. Delivers extended anti-shudder durability. Delivers extended clutch-friction durability. Excellent corrosion and foaming resistance. Excellent thermal and oxidative stability that helps to prevent deposits and oil thickening.