AMSOIL SEVERE GEAR® 75W-90 100% SYNTHETIC GEAR LUBE

AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube delivers heavy-duty wear protection and thermal stability for differentials, manual transmissions and transfer cases in trucks, SUVs, Jeeps, heavy equipment and anything else you put through hard service. It is built from the ground up for the kind of punishment that breaks down conventional gear oils.

Modern vehicles generate more heat and more torque than ever. Pickup trucks like the Ford F-150, Ram 1500, Chevy Silverado and Toyota Tacoma are routinely used for towing, hauling and off-road work that pushes differential temperatures well beyond what a conventional 75W-90 gear oil can handle. When gear lube loses viscosity under that kind of heat, metal-to-metal contact follows. That accelerates wear on ring and pinion gears, spider gears and bearings, and can lead to expensive differential rebuilds.

CONTROLS THERMAL RUNAWAY
Thermal runaway happens when a gear lube can't control friction under high-stress conditions. Friction generates heat, heat thins the oil, thinner oil generates more friction, and the cycle feeds on itself. AMSOIL SEVERE GEAR 75W-90 is formulated to break that cycle. It maintains its viscosity under extreme loads and high temperatures, keeping friction and heat in check instead of letting them compound. This directly protects differentials in towing applications, steep-hill driving and stop-and-go commercial use where sustained high loads are unavoidable.

IRON-SULFIDE BARRIER COATING FOR EXTREME-PRESSURE PROTECTION
Proprietary AMSOIL additives form an iron-sulfide barrier coating on gear surfaces. This coating acts as the last line of defense against wear, pitting and scoring under boundary lubrication conditions, when metal surfaces are under enough pressure that the oil film alone isn't sufficient. For trucks towing fifth wheels, trailers or heavy payloads, and for Jeep Wrangler and Toyota 4Runner owners running hard off-road, this extreme-pressure protection is what keeps ring and pinion gear sets alive over the long haul.

EXCELS IN TEMPERATURE EXTREMES
SEVERE GEAR 75W-90 resists breakdown from high heat, preventing acid and carbon/varnish formation that degrades seals and shortens component life. On the cold side, its wax-free synthetic construction delivers a Brookfield viscosity of 31,720 cP at -40°C (ASTM D2983), well within the 75W low-temperature requirements. That means improved cold-weather shifting in manual transmissions, better cold-flow to gear surfaces at startup, and improved fuel economy compared to conventional gear oils that thicken up in winter. With a pour point of -43°F (-45°C) and a flash point of 222°F (431.3°F), it covers a wide operating range from subzero mornings to summertime towing across the desert.

REDUCES OPERATING TEMPERATURES AND EXTENDS EQUIPMENT LIFE
Lower friction means lower operating temperatures. SEVERE GEAR 75W-90 reduces heat buildup in differentials and manual transmissions, which directly extends the service life of the oil itself, the seals and the gear components. A viscosity index of 152 (ASTM D2270) means the oil resists thinning at high temperatures while remaining fluid in the cold, providing consistent protection across a broad temperature range. That stability translates to longer intervals between changes and less wear accumulation over time.

BUILT FOR LIMITED-SLIP DIFFERENTIALS
SEVERE GEAR 75W-90 contains friction modifiers for compatibility with most limited-slip differentials. For applications that require additional limited-slip friction modifier, add AMSOIL Slip Lock. This covers a wide range of trucks and SUVs, including GM, Ford, Ram and Toyota limited-slip equipped axles, without needing a separate friction modifier additive in most cases.

Specifications and Compatibility
AMSOIL SEVERE GEAR 75W-90 is recommended for differentials, manual transmissions and other gear applications requiring any of the following specifications: API GL-5, MT-1, MIL-PRF-2105E, Dana SHAES 234 (formerly Eaton PS-037), Mack GO-J, and other GL-5-based specifications from Ford, GM and Chrysler. It can also be used in axles where an API GL-4 lubricant is recommended. Compatible with conventional and synthetic gear oils, though mixing will shorten oil life expectancy and reduce performance benefits. AMSOIL does not support extended drain intervals where oils have been mixed. Aftermarket oil additives other than those specified by AMSOIL are not recommended.

Service Life
For cars, SUVs and light trucks in normal service: drain at 100,000 miles (161,000 kilometers) or according to the owner's manual, whichever is longer. For severe service (towing, hauling, steep-hill driving, commercial use, high ambient temperatures): drain at 50,000 miles (80,500 kilometers) or according to the owner's manual, whichever is longer. Heavy-duty Class 8 line haul applications support up to 250,000 miles (402,500 kilometers) or three years following OEM drain intervals for synthetic oil. Vocational and delivery applications support up to 120,000 miles (193,200 kilometers) or three years. Heavy-duty off-road applications support up to 100,000 miles or two years. Change gear oil more frequently when operating in dusty or dirty conditions unless the gear system is properly sealed and equipped with membrane-type breathers. AMSOIL does not support extended drain intervals where water contamination occurs.