Red Line 75W90 NS GL-5 Synthetic Gear Oil

Red Line 75W90 NS GL-5 Synthetic Gear Oil - 1 Quart

The Ultimate Transaxle Fluid for Rapid Synchronization and Maximum Lock-Up

Experience a new level of shifting precision with Red Line 75W90 NS. Specifically engineered for manual transmissions and transaxles that specify a GL-5 gear oil—common in Ferrari, Porsche, and Subaru applications—this fluid balances extreme gear protection with the specific frictional properties needed for synchronizers to work correctly. Because it doesn't contain the "slipperiness" additives found in standard differential oils, it is also the preferred choice for racers who want maximum lock-up from their clutch-type limited-slip differentials or for those who wish to "tune" their LSD by adding friction modifiers in precise increments.

What’s Included in the Box:

- (1) 1 Quart (0.946L) Bottle: Standard neck design compatible with most common fluid transfer pumps.

The Red Line Advantage

- "Non-Slip" Technology: Designed without friction modifiers to help synchronizers slow down and lock gears quickly, eliminating gear clash and reducing shift effort.

- Polyol Ester Base Stocks: Provides an unshearable oil film and superior thermal stability, ensuring your gears remain protected during high-speed, high-heat operation.

- Extreme Pressure (EP) Protection: API GL-5 rated to handle the intense loads of hypoid gear sets and transaxles without sacrificing shift quality.

- Yellow Metal Compatibility: Formulated to be non-corrosive, making it completely safe for brass, bronze, and copper synchronizer materials.

- Customizable LSD Performance: Ideal for "weak" limited-slip differentials that need more grab, or for use as a base fluid to be tuned with Red Line Limited Slip Friction Modifier.

Product Specifications

- Part Number: 58304

- Viscosity Grade: SAE 75W-90

- Standard: API GL-5, GL-6, MT-1, MIL-L-2105E, SAE J2360

- Viscosity at 100°C: 15.6 cSt

- Viscosity Index: 185

- Flash Point: 221°C / 430°F

- Pour Point: -45°C / -49°F

Primary Vehicle Compatibility

- Subaru: Ideal for WRX and STI transaxles (front diff and gearbox combo).

- Porsche & Ferrari: Used in many transaxle models requiring GL-5 protection.

- Mitsubishi: Popular for Evolution 4-9 high-torque transmission builds.

- Classic Muscle Cars: Perfect for Ford Top Loader, Muncie, and Borg-Warner T-10 gearboxes.

Precision Tip: If you are using this fluid in a street-driven limited-slip differential and experience "chatter" or noise during tight turns, simply add Red Line Limited Slip Friction Modifier (Product #80301) in 1oz increments until the noise disappears. For most Subaru owners, this NS fluid is the "holy grail" for fixing the common 1st-to-2nd gear crunch.