ABSTRACT
Gear protection performance, load carrying properties, peak temperature reduction characteristics and fuel economy improvement were examined by a high temperature and high speed test, modified L-42 test, a peak temperature measurement and a chassis roll test, respectively. It is important to predict the performance characteristics of the newly developed automotive gear oils. Using a bench hyoid gear tester, several kinds of the gear tests were carried out to confirm the properties of the new S-P type candidate oils. Innovations such as the use of smaller and/or lightweight axles, new type transfer gears for a four wheel drive, increasing engine output and newly designed transaxles, all contribute to this increase in performance requirement. Passenger cars are often driven at very rapid speed on express highways, especially in Europe and some troubles in powertrain lubrications have been reported. Roles of sulfur and phosphorus components in S-P package additives were also investigated.
