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The low-temperature portion of SAE J300 Engine Oil Viscosity classification has been analyzed in terms of its scope and its use by domestic engine manufacturers. Also, its ability to protect against pumping failures has been analyzed. The analysis shows that the use is not in accord with the stated scope, and that protection against pumping failures is not adequate for a significant portion of engines. An alternative scope for J300 is proposed which is based on minimum-use temperatures for each grade. The results of this analysis will assist in formulating a future revision of SAE J300 based on the results of the ASTM Low Temperature Engine Performance program.

Current specifications for automatic-transmission fluids and gear oils have viscosity limits which are determined by ASTM D 2983. However, that test is plagued by poor precision. This paper describes the development of a method using the Mini-Rotary Viscometer to make the determination of apparent viscosity at the same nominal shear stress as ASTM D 2983. In this test procedure, samples are cooled in a manner similar to that described in ASTM D 2983. Experimental data were obtained on a mixture of 17 automatic-transmission and gear-oil fluids that included a number of different formulation strategies and commercial products. The results of this method yield a nearly one to one correlation with the results determined by ASTM D 2983.