CORRELATION OF BENCH OXIDATION TESTS WITH TRANSMISSION TEST PERFORMANCE OF AUTOMATIC TRANSMISSION FLUIDS

Most laboratory oxidation tests are of little value for predicting the performance of transmission fluids in service. This is because catalytic conditions and temperatures are unrealistic, and the wrong criteria of performance are used. Usually the tests prescribe only a few analyses, and the fluid properties observed are not those most likely to indicate performance in a transmission. A revised Allison Type C Oxidation Test is shown to be useful in predicting transmission test results. The effects of base stock type and of additives are illustrated. Agreement of the bench test data with results in automatic transmission oxidation tests is shown. The low cost screening test has led to the development of highly stable, detergent, automatic transmission fluids.