Redline MT-85 75W85 GL-4 Gear Oil Quart

Redline MT-85 75W85 GL-4 Gear Oil (Quart)

MT-85 Gear Oil is a full-synthetic, ester-based lubricant from Red Line, built for manual transmissions and front-wheel-drive transaxles. It’s a popular choice for Nissan 350Z and 370Z gearboxes, along with most Maxima, Altima, and Sentra manuals. It’s also a common fit for Mitsubishi Evolution, Hyundai, Kia, and Quaife synchro transmissions. Many NV4500 truck transmissions, including those in Chevy Silverado and Dodge Ram trucks, also run well on it.

How MT-85 Gear Oil Performs

This oil is less slippery than a typical GL-5 differential fluid. That gives it the synchronizer coefficient of friction a manual gearbox actually needs. The result is quicker, cleaner shifts and less notchy engagement, even in cold weather. It’s also safe for brass synchros. Unlike most GL-5 oils, it lacks the reactive sulfur compounds that can damage brass components over time. A shear-stable formula resists breakdown over extended service, keeping viscosity consistent in both warm and cold conditions. That consistency also helps cut down on gear noise.

Typical Properties

• API Service Class: GL-4
• SAE Viscosity Grade (Gear Oil): 75W85
• SAE Viscosity Grade (Motor Oil): 5W30
• Viscosity @ 40°C: 62 cSt
• Viscosity @ 100°C: 12 cSt
• Viscosity Index: 198
• Pour Point: -48°C (-54°F)

Applications and Compatibility

This oil satisfies the gear oil viscosity requirements of 85W and 75W85. It also covers SAE 30 and 5W30 motor oil viscosities. Red Line recommends it for GL-1, GL-3, and GL-4 applications, as well as anywhere a special synchromesh fluid is specified. It’s fully compatible with petroleum-based and other synthetic gear oils, so topping up an existing fill is straightforward. Because it’s blended for synchronized manual gearboxes rather than differentials, it’s not recommended for use in hypoid-gear differentials.

This Quart size suits a single transmission fill; a Gallon size is also available for larger jobs. Not sure if MT-85 suits your gearbox? Get in touch and we’ll help you choose. For the full technical data sheet, see Redline’s official product page.