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The friction characteristics of several DEXRON®-III automatic transmission fluids were examined in a variety of friction tests. These evaluations included tests with SAE No. 2 Friction Machines using either Band or Plate heads, breakaway friction tests, and low-sliding speed friction tests. The effect of bulk fluid temperature on friction performance was examined in band tests and in breakaway tests using the plate clutch apparatus. The DEXRON®-III fluids were compared to the previous generation automatic transmission fluids. Results showed that the DEXRON®-III fluids exhibited more desirable friction characteristics; for example, with the DEXRON®-III fluids in the band machine, dynamic friction remained stable during sustained operation at high temperature, whereas with DEXRON®-IIE fluids, dynamic friction decreased as much as 25%.

An engine dynamometer test procedure was developed for evaluating fuel and fuel additive effects on the plugging of port fuel injectors. The test procedure was shown to adequately reflect the influence of fuels and additives on injector plugging in vehicles. Injector soak temperature and fuel system configuration were found to be critical factors in obtaining an acceptable engine-vehicle correlation. Injector plugging occurred in as little as 10 hours with a high-olefin base fuel; in contrast, plugging took two orders of magnitude longer with a high-quality, detergent-containing, commercial-type fuel. Furthermore, fuel additives greatly increased plugging resistance with the OEM, pintle-type injectors. Injector design alterations were also shown to be important. Pintle-type injectors with flared, aluminum caps extended plugging time considerably relative to the same injector design with plastic caps. Director plate-type injectors were much better still.