THE majority of car manufacturers recommended to their customers two or more seasonal changes of axle and transmission lubricants on 1931 to 1940 cars, Mr. James reports. He also notes a slow increase in the number recommending a single all-season lubricant and that the use of three and four seasonal changes now has disappeared.
Answering the question: “Why do not the manufacturers agree on a set of temperature ranges for the recommendation of seasonal changes for transmission and for rear-axle lubricants or both, so that their customers will not be confused from year to year?” he assures that they would do so just as they have done in the case of temperature ranges for motor oils.
Emphasizing the importance of the temperatures, pressures, and rubbing speeds encountered in rear-axle and transmission gearing, he states that they are probably the most important factors in the selection of suitable lubricants.
The considerable data presented in this paper include results of tests on seven hypoid lubricants made on the dynamometer and in trucks on the road; comparisons of carrier stiffness and corrective gear cutting for rear axles; and test results on five present-day test machines for three of the current types of hypoid lubricants.