AMSOIL SEVERE GEAR® 80W-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® 80W-90 100% Synthetic Gear Lube.
AMSOIL SEVERE GEAR 80W-90 100% Synthetic Gear Lube
AMSOIL SEVERE GEAR 80W-90 100% Synthetic Gear Lube (product code AGL) is a premium-grade GL-5 synthetic gear oil for rear differentials, manual transmissions, and other axle and gear applications that call for an 80W-90 viscosity. It is the synthetic upgrade path for older trucks, classic vehicles, hot-climate light-truck differentials, and heavy-duty hardware specified for an API GL-5 80W-90 fluid.
Iron-sulfide barrier coating and severe-duty wear protection
Severe Gear 80W-90 is built on synthetic base oils with a proprietary AMSOIL extreme-pressure additive package that forms an iron-sulfide barrier coating on gear surfaces. The barrier coating is the ultimate line of defense against wear, pitting, and scoring in pinion-and-ring gear sets that see repeated shock loading from towing, hauling, plowing, off-road use, steep-hill driving, rapid acceleration, and frequent stop-and-go duty.
Thermal runaway control under load
Differentials and gearboxes under sustained load can spiral into thermal runaway, a condition where the lubricant loses its ability to control friction and operating temperature climbs without limit. Severe Gear 80W-90 inhibits this rapid lubricant degradation, helping the gearset hold film strength when ambient temperatures, hill grades, payload, and trailer tongue weight all stack up at once. Lower operating temperatures translate to longer oil seal life and longer equipment life.
Hot and cold temperature stability
Severe Gear 80W-90 performs at both ends of the temperature scale. The formula resists high-heat breakdown that drives acid and carbon/varnish formation, and the wax-free construction improves cold-flow properties for easier cold-weather shifting and reduced cold-start drag in differentials. The 80W-90 grade carries a kinematic viscosity of 15.5 cSt at 100 C and 120.2 cSt at 40 C (ASTM D445), a viscosity index of 135 (ASTM D2270), a Brookfield viscosity of 46,200 cP at -26 C (ASTM D2983), and a pour point of -42 C / -44 F (ASTM D97).
Rust, corrosion, and foam control
Differentials in seasonal trucks, marine trailers, plow rigs, and off-road equipment sit through humid, salty, or wet operating cycles. Severe Gear 80W-90 protects against rust and corrosion inside the housing and turns in a 1b copper corrosion rating at 121 C / 250 F over three hours (ASTM D130). Foam stability comes in at 0/0, 0/0, 0/0 (ASTM D892), keeping a stable film across the gear teeth.
Long service life across heavy-duty equipment
Severe Gear synthetic chemistry is shear-stable, holds its viscosity across long drain intervals, and inhibits the rapid lubricant degradation seen with conventional 80W-90 mineral gear oils. The result is a service life suited to heavy-duty trucks, tow trucks, race cars, tractors, motor homes, and farm and construction equipment.
Recommended applications and service intervals
Severe Gear 80W-90 (AGL) is built for differentials, manual transmissions, and other gear applications that call for any of the following industry, military, or OEM gear-lube specifications:
API GL-5 and MT-1, plus MIL-PRF-2105E, Dana SHAES (formerly Eaton PS-163), and Mack GO-J, plus other GL-5 based specifications from Ford, GM, and Chrysler. Severe Gear 80W-90 can also be used in axles where an API GL-4 lubricant is recommended.
Cars, SUVs, and light trucks in differential service: drain at 100,000 miles (161,000 km) in normal service or follow the owner's manual interval, whichever is longer. In severe service, drain at 50,000 miles (80,500 km) or follow the owner's manual interval, whichever is longer.
Heavy-duty service in differentials: follow the OEM drain interval for synthetic oil up to 250,000 miles (402,500 km) or three years for Class 8 line-haul, up to 120,000 miles (193,200 km) or three years for vocational and delivery, and up to 100,000 miles or two years for off-road, whichever comes first.
Non-differential gear applications and water-contamination exclusions: follow the OEM normal or severe synthetic-oil interval, or where no synthetic interval is published, drain at twice the conventional-oil interval. Extended drain intervals are not supported where water contamination occurs, and gear oil should be changed more frequently in dusty or dirty operating conditions unless the gear system is properly sealed and equipped with membrane-type breathers.
Severe Gear 80W-90 is compatible with most limited-slip differentials. For applications that require an additional limited-slip friction modifier, add AMSOIL Slip Lock. The formula is also compatible with conventional and synthetic gear oils, but mixing shortens oil life and reduces performance benefits, and extended drain intervals are not supported when oils have been mixed. Aftermarket oil additives other than those specified by AMSOIL are not recommended for use with AMSOIL gear oil. To confirm the right grade and specification for a specific axle, transfer case, or gearbox, work through the AMSOIL Vehicle Lookup Guide and the 80W-90 Gear Oil Guide.
Typical technical properties
Property
Value
Kinematic Viscosity at 100 C, cSt (ASTM D445)
15.5
Kinematic Viscosity at 40 C, cSt (ASTM D445)
120.2
Viscosity Index (ASTM D2270)
135
Brookfield Viscosity, cP at -26 C (ASTM D2983)
46,200
Flash Point, C (F) (ASTM D92)
208 (406)
Pour Point, C (F) (ASTM D97)
-42 (-44)
Copper Corrosion at 121 C / 250 F, 3 hr (ASTM D130)
1b
Foam Stability (ASTM D892)
0/0, 0/0, 0/0
Order Severe Gear 80W-90 Synthetic Gear Lube
Severe Gear 80W-90 Synthetic Gear Lube is available in Quart Easy-Pack (AGLPK-EA), quart bottle (AGLQT-EA), case of 12 Quart Easy-Packs (AGLPK-CA), 5 gallon pail (AGL05-EA), 16 gallon keg (AGL16-EA), 55 gallon drum (AGL55-EA), and 275 gallon tote (AGL27-EA) sizes. Using AMSOIL synthetic lubricants and practicing extended drain intervals does not void a new vehicle or equipment manufacturer warranty, and all AMSOIL lubricants and filters are backed by the AMSOIL Limited Warranty. Match the right axle and gearbox grade with the 80W-90 Gear Oil Guide, match the right product in the AMSOIL Vehicle Lookup Guide, then order AMSOIL SEVERE GEAR 80W-90 100% Synthetic Gear Lube.
Severe Gear 80W-90 (AGL) is a 100 percent synthetic, extreme-pressure GL-5 gear lube designed for differentials, manual transmissions, and other gear applications where the equipment manufacturer specifies an 80W-90 viscosity grade. It is well suited to older pickups, classic trucks and SUVs, hot-climate light-truck rear axles, heavy-duty trucks, motor homes, race cars, tractors, and farm and construction equipment that see towing, hauling, plowing, off-road service, or sustained high ambient temperatures.
What specifications does Severe Gear 80W-90 meet?
The 80W-90 grade carries API GL-5, MT-1, MIL-PRF-2105E, Dana SHAES (formerly Eaton PS-163), and Mack GO-J, along with other GL-5 based specifications from Ford, GM, and Chrysler. Severe Gear 80W-90 can also be used in axles where an API GL-4 lubricant is recommended. Confirm the specific axle or gearbox spec before changing fluid.
How often should Severe Gear 80W-90 be changed in a differential?
In cars, SUVs, and light-truck differentials, the normal-service drain is 100,000 miles (161,000 km) or the owner's manual interval, whichever is longer. In severe service, the drain falls to 50,000 miles (80,500 km) or the owner's manual interval, whichever is longer. Class 8 line-haul, vocational/delivery, and heavy-duty off-road differentials follow the OEM drain interval for synthetic oil up to 250,000 miles, 120,000 miles, or 100,000 miles, respectively, with time-based limits of two to three years.
Is Severe Gear 80W-90 safe for limited-slip differentials?
Severe Gear 80W-90 is compatible with most limited-slip differentials. For axles that call for an additional limited-slip friction modifier (for example, to quiet clutch chatter on tight turns), add AMSOIL Slip Lock to the differential along with Severe Gear 80W-90.
Can Severe Gear 80W-90 be mixed with conventional gear oil?
Severe Gear 80W-90 is compatible with conventional and synthetic gear oils, but mixing shortens oil life and reduces performance benefits, and extended drain intervals are not supported when oils have been mixed. Aftermarket oil additives other than those specified by AMSOIL are not recommended for use with AMSOIL gear oil.
Will switching to Severe Gear synthetic gear lube void a new vehicle warranty?
No. Using AMSOIL synthetic lubricants and practicing extended drain intervals does not void a new vehicle or equipment manufacturer warranty, and AMSOIL products are backed by the AMSOIL Limited Warranty.
Should this axle run an 80W-90 or a 75W-90 instead?
The right grade depends on the axle or gearbox manufacturer specification and the operating temperature range. Severe Gear is offered in 75W-85 (SVL), 75W-90 (SVG), 75W-110 (SVT), 75W-140 (SVO), and 80W-90 (AGL). Use the AMSOIL Vehicle Lookup Guide and the 80W-90 Gear Oil Guide to confirm the correct grade for the equipment.
