Procedures for the Evaluation of Automatic Transmission Fluids

The development of more powerful engines with higher operating temperatures, the trend toward lower axle ratios, and increased use of passenger cars for trailer hauling have imposed greater demands on the durability of transmission fluid. What had been reported in the past as clutch failures might have been more accurately recognized as oil failures due to lack of friction retention. This paper describes Chevrolet's efforts to define desirable fluid characteristics and to develop test procedures to evaluate transmission fluids.