JASO M358

JASO M358 is a specification developed by the Japanese Association of Standardization of Motor Oils (JASO) for automatic transmissions, in particular continuously variable (CVT) gearboxes in motorcycles and scooters. Technically it requires stable viscosity over a wide temperature range, high oxidation resistance, effective wear protection, and the maintenance of an optimal friction coefficient, which ensures smooth CVT operation and prevents belt slip. The specification is targeted at 4‑stroke engines with automatic transmissions, including popular models from Honda, Yamaha, Suzuki and Kawasaki, as well as light commercial scooters where quick cold pumpability and seal compatibility are important. JASO M358 does not impose restrictions regarding SAPS, DPF, or catalytic systems, as it is applied exclusively in transmissions, not in emission systems. Although new products often have expanded parameters, they remain compatible with the older JASO M345 requirements, allowing safe lubricant replacement without voiding warranty conditions.