Automatic Transmission Fluid Development: Reaching New Levels of Friction Durability

This paper reports development of a new automatic transmission (AT) fluid (ATF) with enhanced durability for the Asian marketplace. The authors contend the new step-automatic transmission hardware, such as wet starting clutches, new friction materials, dual clutches and six- and seven-speed ATs, create the need for enhanced levels of friction durability from the ATF. The new challenge from such hardware for the fluid developer lies in simultaneously meeting more stringent wear, extreme pressure (EP), friction durability and torque capacity requirements.

The new additive chemistry, when used in a mineral oil base fluid, is capable of 1000+ hours in JASO M349 LVFA durability testing, a 16-fold increase over the JASO M349 reference ATF Toyota T-III. This performance easily doubles that of the currently most durable Asian ATFs, while offering better anti-wear and EP performance.