Red Line MT-90 75W90 Synthetic Manual Transmission Oil (1 Qt.) (Case of 12)

Red Line MT-90 is a full synthetic, ester-based gear oil built specifically for manual transmissions and front-wheel-drive transaxles. At 75W90 GL-4, it sits in the sweet spot for many import and domestic manual gearboxes that call for a medium-weight gear oil.

One of the key technical points with MT-90 is the GL-4 rating. Unlike GL-5 oils, which contain reactive sulfur compounds that can attack brass synchronizers over time, GL-4 oils are safe for brass synchros while still providing strong film strength for gear protection. Red Line's ester-based synthetic formula resists shear and breakdown, maintaining consistent viscosity across a wide temperature range. The pour point sits at minus 45 degrees Celsius, so cold-weather shifting stays smooth even in harsh conditions.

Drivers who have switched to MT-90 commonly report smoother, more precise shifts and noticeably less gear whine. It is a popular choice in Nissan, Toyota, Mazda, and Subaru manual transmissions, though it suits any application calling for a 75W90 GL-4 lubricant. At one quart per bottle, most transmissions require two to three quarts for a complete fluid change, so plan accordingly.