AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube
SEVERE GEAR is designed for those who demand the best. Engineered with high film strength for high-load demands. Reduces friction and provides the ultimate protection against wear. Excels in extreme temperatures. Helps maintain efficiency and outperforms conventional gear oils. Excellent for all cars and trucks, but especially well-suited for towing, hauling, racing, commercial use, or other severe duty.
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Product data sheets
View, download, or save a copy of the Product Data Sheet or Safety Data Sheet for AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube.
AMSOIL Severe Gear 75W-90 100% Synthetic Gear Lube
Severe Gear 75W-90 is a 100% synthetic, extreme-pressure gear lube engineered for the differentials, axles, and gear sets in pickups, SUVs, vans, and other hard-working vehicles that call for an SAE 75W-90, API GL-5 lubricant. The formula carries built-in friction modifiers for limited-slip differentials and is designed to hold viscosity under towing, hauling, off-road, and high-heat service.
Iron-sulfide barrier film for severe-duty wear protection
Differentials run hypoid gears that combine high sliding loads with shock from acceleration, throttle changes, and uneven traction. Severe Gear 75W-90 uses proprietary AMSOIL extreme-pressure additives that form an iron-sulfide barrier film on gear faces, providing a tenacious line of defense against wear, pitting, and scoring. The synthetic base oil maintains viscosity for long-lasting protection against metal-to-metal contact in the loaded ring-and-pinion contact patch.
Controls thermal runaway and resists high-heat breakdown
Under sustained heavy load, a gear lubricant that cannot control friction enters thermal runaway, where rising oil temperature accelerates oxidation, which raises friction further and feeds the cycle. Severe Gear 75W-90 is engineered to interrupt that loop by controlling friction and resisting breakdown from high heat, helping prevent acid formation and carbon and varnish deposits on gear and bearing surfaces. The result is slower lubricant degradation, lower operating temperatures, and longer seal, gear, and bearing life in towing and hauling duty.
Wax-free synthetic chemistry for cold flow
The wax-free synthetic construction stays fluid in extreme cold, with a -43 degrees C (-45 degrees F) pour point and a Brookfield viscosity of 61,940 cP at -40 degrees C measured per ASTM D2983. That cold-flow behavior reaches lubricated surfaces faster on cold starts, improves cold-weather shifting in manual gearboxes, and helps reduce the parasitic gear-oil drag that conventional 75W-90 lubricants impose on fuel economy in low temperatures.
Friction modifiers for clutch-type limited-slip differentials
Severe Gear 75W-90 is formulated with friction modifiers for limited-slip differentials and is compatible with most clutch-type LSDs without a separate additive. For applications that call for additional limited-slip friction modifier, or to address clutch chatter under low-speed turning, dosing with AMSOIL Slip Lock Differential Additive is the supported path. Aftermarket gear oil additives outside the AMSOIL product line are not recommended for use with Severe Gear.
Recommended applications and service intervals
Severe Gear 75W-90 is intended for differentials, manual transmissions, and other gear applications that require an SAE 75W-90 GL-5 lubricant, including specifications API GL-5, MT-1, MIL-PRF-2105E, Dana SHAES 256 (formerly Eaton PS-163), Mack GO-J, and other GL-5-based specs from Ford, GM, and Chrysler. Match the master product code and viscosity grade to the application using the AMSOIL vehicle lookup guide.
Cars, SUVs, and light trucks (normal service): drain at 100,000 miles (161,000 km) or per the owner's manual, whichever is longer.
Cars, SUVs, and light trucks (severe service such as towing, hauling, plowing, racing, off-road, frequent stop-and-go, or high ambient temperatures): drain at 50,000 miles (80,500 km) or per the owner's manual, whichever is longer.
Heavy-Duty Class 8 line haul: follow the OEM drain interval for synthetic oil up to 250,000 miles (402,500 km) or three years, whichever comes first. Vocational and delivery: up to 120,000 miles or three years. Heavy-Duty off-road: up to 100,000 miles or two years.
For non-differential applications without a published synthetic interval, drain at twice the conventional oil interval. Service the lube more frequently in dusty or dirty conditions when the gear system lacks a sealed, membrane-type breather.
Severe Gear 75W-90 is compatible with conventional and synthetic gear oils, but mixing shortens oil life expectancy and reduces performance benefits, and extended drain intervals are not supported on a mixed fill. Extended drains are also not supported where water contamination is possible. For limited-slip clutch chatter or LSDs that specify an additional friction modifier, pair with AMSOIL Slip Lock. Use Severe Gear in axles where an API GL-5 lubricant is called for.
Typical technical properties
Property
Value
Kinematic Viscosity at 100 degrees C, cSt (ASTM D445)
16.0
Kinematic Viscosity at 40 degrees C, cSt (ASTM D445)
97.8
Viscosity Index (ASTM D2270)
175
Brookfield Viscosity, cP at -40 degrees C (ASTM D2983)
61,940
Flash Point, degrees C (degrees F) (ASTM D92)
222 (431.6)
Pour Point, degrees C (degrees F) (ASTM D97)
-43 (-45)
Copper Corrosion at 121 degrees C / 3 hr (ASTM D130)
1b
Foam Stability (ASTM D892)
0/0, 10/0, 0/0
Order AMSOIL Severe Gear 75W-90 100% Synthetic Gear Lube
Master product code SVGPK-EA ships as a Quart Easy-Pack designed for clean, fast differential fills. Additional package options include the SVGQT-EA quart bottle, SVGPK-CA case of 12 Quart Easy-Packs, SVGQT-CA case of 12 quart bottles, SVG05-EA 5 gallon pail, SVG16-EA 16 gallon keg, and SVG55-EA 55 gallon drum for fleet and shop accounts. Severe Gear 75W-90 is backed by the AMSOIL Limited Warranty. For viscosity comparisons across the family and limited-slip guidance, see the AMSOIL 75W-90 gear oil guide, then place an order at the Severe Gear 75W-90 product page.
I have used this product for many years now after experimenting with HD Screaming Eagle, Lucas, Mobile 1, the purple stuff and red stuff. None compare to Amsoil. Much smoother shifting and prolonged protection for hard shifts and hot days.
By Michael from San Antonio on July 06, 2026.
Would recommend this to a friend.
LOVE the EZ pack!
Not a review of the product, as much as the container- I changed the old in both diffs and the fluid in my transfer case, and these collapsible bottles were invaluable and let me add fluids without using a transfer pump. So cool, I hadn’t seen these before.
SAE 75W-90 is a hypoid gear oil viscosity used in many passenger and light-truck differentials and in some manual transmissions and transfer cases. Severe Gear 75W-90 covers axles and gear sets that specify a 75W-90 API GL-5 lubricant in pickups, SUVs, and vans, including towing, hauling, off-road, and commercial duty cycles where conventional 75W-90 thins out under heat.
Is Severe Gear 75W-90 GL-5 or GL-4?
Severe Gear 75W-90 meets API GL-5 and API MT-1 alongside MIL-PRF-2105E, Dana SHAES 256 (formerly Eaton PS-163), and Mack GO-J. GL-5 is the high extreme-pressure category for hypoid differentials and most modern light-truck and SUV axles. Manual transaxles that specifically call for a GL-4 only fluid (common in some European and synchromesh applications) need a different lubricant designed for that specification.
Does Severe Gear 75W-90 work in limited-slip differentials, or is Slip Lock required?
Severe Gear 75W-90 contains friction modifiers and is compatible with most clutch-type limited-slip differentials without an additional additive. If the axle manufacturer calls for a separate friction modifier, or if low-speed clutch chatter shows up after a fill, AMSOIL Slip Lock Differential Additive is the supported supplement. Aftermarket additives outside the AMSOIL line are not recommended.
How often should differential fluid be changed?
For cars, SUVs, and light trucks, Severe Gear 75W-90 supports a 100,000 mile (161,000 km) normal-service drain and a 50,000 mile (80,500 km) severe-service drain, or the owner's manual interval if it is longer. Severe service includes towing, hauling, steep-hill driving, racing, off-road use, frequent stop-and-go, and high ambient temperatures. Service the gear oil more often in dusty conditions or any time water contamination is possible.
Can Severe Gear 75W-90 be mixed with conventional or other synthetic gear oils?
Severe Gear 75W-90 is compatible with conventional and synthetic gear oils, so a top-off mix will not damage the differential. Mixing, however, shortens the oil's effective life and reduces the performance benefits of the synthetic base oil and additive system, and AMSOIL does not support extended drain intervals on a mixed fill. The cleanest approach is a full drain and refill with Severe Gear 75W-90 to reset the service interval.
Will Severe Gear 75W-90 fit a Ford F-150, Chevy Silverado, Ram 1500, Toyota Tundra, or Jeep Wrangler differential?
Severe Gear 75W-90 fits axles that call for a 75W-90 API GL-5 hypoid gear oil and is compatible with GL-5-based specifications from Ford, GM, and Chrysler. Confirm the exact viscosity grade and capacity for the model year, axle code, and front or rear position with the AMSOIL vehicle lookup guide before ordering, since some half-ton trucks and SUVs spec a heavier 75W-110 or 75W-140 in the rear axle.
