Proposal of New Criteria and Test Methods for the Dynamic Performance of ATF

Recently in the world, many modifications and improvements have been taking place in automatic transmission fluid (ATF) in order to get more excellent performance and durability of automatic transmission.

The most important criterion for the improvement of ATF is a superior friction characteristic. To consider the performance of ATF, we have investigated the correlation of criteria between actual vehicle tests and bench-scale tests (e.g. SAE#2 Friction Test). And it was proved that conventional criteria and test methods for bench-scale tests were not enough to give best prediction of actual vehicle performance especially for shift quality, anti-shudder performance and static torque capacity which were regarded as of major importance for the development.

Based on the findings, we have considered new criteria and test methods for the frictional characteristics, and specific requirements for ATF have been proposed from the standpoint of actual vehicle performance.