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Studies into a material to improve the power density of powershift transmissions and brake systems have revealed that the porosity and elasticity of wet friction materials have a large influence on dynamic friction coefficient and energy absorption capacity. From this basic idea, a new wet friction material for heavy-duty application has been developed. This friction material is a resin molding composed principally of high heat-resistant resin, graphite and fibers. Its advantages include a far higher energy absorption capacity than current sintered bronze material, a high friction coefficient, excellent slip endurance, and high thermal stability. These characteristics are mainly the result of a manufacturing method which provides low elasticity and high porosity, as well as necessary strength. The results of extensive testing confirmed the concept of the new friction material.

A higher versatility is required from medium size bulldozers as vehicles other than large size bulldozers. Therefore the design concept of the transmission for medium size bulldozers has to be changed to that of large size bulldozers. We adopted combination of high capacity torque convertor and low reduction (high output speed) cross ratio gear train for medium size bulldozers' transmission. We also evaluated the advantages and disadvantages of rotating clutches, and decided not to use the rotating clutches in new transmission for medium size bulldozers, because of their disadvantages. By these design concepts and material technology, we can reduce the transmission size and improve the efficiency.