Nippon Oil Corporation

Toyota Jidosha Kabushiki Kaisha

Toru Matsuoka

Masato Takahashi

Akihiko Ichikawa

Osamu Kurosawa

Yoshikazu Yamamoto

Koji Saito

Kazuo Yamamori

Masaaki Itou

Tetuzo Yoneda

Lubricating oil compositions for transmissions comprises (A) a lubricating base oil with a kinematic viscosity at 100&#xb0; C. adjusted to 1.5 to 6 mm/s, composed of (A1) a lubricating base oil with a kinematic viscosity at 100&#xb0; C. of 1.5 mm/s or higher and lower than 7 mm/s or (A1) the lubricating oil and (A2) a lubricating base oil with a kinematic viscosity at 100&#xb0; C. of 7 to 50 mm/s, blended with (B) a poly(meth)acrylate-based additive, so that the composition has a kinematic viscosity at 100&#xb0; C. of 3 to 8 mm/s and a viscosity index of 95 to 200, (A) and (B) fulfill a specific requirement. The compositions achieve long fatigue life though having low viscosity.

Lubricating oil composition for transmission

Provided is a lubricating oil composition for manual transmissions which has anti-seizure properties for shift forks and can provide manual transmissions with excellent shifting characteristics though it has a low viscosity and can save fuel to be used in automobiles. The lubricating oil composition for manual transmissions comprises a lubricating base oil with a kinematic viscosity at 100&#xb0; C. of 4 to 6 mm/s, on the basis of the total mass of the composition, (A) 0.14 to 0.20 percent by mass in terms of magnesium of magnesium sulfonate, (B) 0.14 to 0.18 percent by mass in terms of zinc of a specific zinc dithiophosphate, (C) 0.3 to 0.5 percent by mass in terms of sulfur of a sulfur-containing extreme pressure additive other than zinc dithiophosphate, and (D) 0.02 to 0.05 percent by mass in terms of phosphorus of an alkyl phosphite, and having a kinematic viscosity at 40&#xb0; C. of 25 to 30 mm/s.

Lubricating oil composition for manual transmission

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Yokohama, Japan

Toru Matsuoka