Patent ID: 6878678

Claim:
An oil composition for automatic transmission equipped with a lock-up clutch and slip control mechanism, said oil composition comprising a carboxylic glyceride mixed with a base oil, and at least one automatic transmission fluid performance additive, the carboxylic glyceride consisting of a carboxylic triglyceride or a mixture of a carboxylic triglyceride and a carboxylic diglyceride, each carboxylic acid residue thereof having a carbon number of 7 to less than 17, the mixing amount thereof being 0.01 wt % to 5 wt % based on the whole composition, the automatic transmission fluid containing said carboxylic glyceride being characterized by a coefficient of friction equal to or greater than 0.13 μ and a time of dμ/dv changing to negative (time of dμ/dv<0) of 57 hours or more.