AMSOILAUTHORIZED DEALER
    (813) 563-2091

    Drivetrain & Differential

    AMSOIL Gear Lube

    The complete AMSOIL synthetic gear lube lineup — SEVERE GEAR for towing and off-road, Long Life for fleet trucks, dedicated formulations for V-Twin, ATV/snowmobile, and marine drivetrains.

    Shop All Gear Lube Save 25% — Become Preferred Customer

    Key Benefits

    • Extreme-pressure protection for heavy towing, hauling, and off-road shock loading
    • Resists thermal runaway at sustained 300°F+ differential temperatures
    • Excellent cold-flow for winter startup, reduced drag, and lower CAFE-cycle losses
    • Outstanding shear stability — viscosity stays in grade across drain interval
    • Protects against rust, corrosion, foam, and seal swell
    • Long Life formulations qualified for 500,000-mile heavy-duty drain intervals
    • Friction modifiers in SEVERE GEAR handle most factory limited-slip differentials
    • Dedicated formulations for marine lower units, V-Twin primary, ATV/snowmobile chaincases
    Watch It Work

    SEVERE GEAR Easy-Pack Demonstration

    Quick Answer

    How do you change differential gear oil without a pump?

    The AMSOIL Severe Gear Easy-Pack allows for a clean, pump-free gear oil change in tight spaces. It is the best gear oil for ATVs, UTVs, and truck differentials that face heavy mud and water contamination in the Florida backcountry.

    The AMSOIL SEVERE GEAR Easy-Pack solves the messiest job in DIY drivetrain service. Its flexible nozzle bends to reach tight fill holes on Dade City pickups, Croom WMA trail rigs, and Hard Rock Off-Road UTVs running Florida mudding trails. Squeeze the entire pack into the diff, transfer case, or manual transmission — no pumps or funnels. The recyclable pouch leaves the same proven SEVERE GEAR extreme-pressure protection that survives water and silt contamination across Central Florida backcountry.

    SEVERE GEAR

    SEVERE GEAR® 100% Synthetic Gear Lube

    AMSOIL's flagship extreme-pressure gear lube line. Built to withstand brutal towing loads, off-road shock loading, and high differential temperatures that destroy conventional gear oils. Available in viscosities to match every axle, transfer case, and manual transaxle on the road.

    Shop AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube
    AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube

    AMSOIL SEVERE GEAR 75W-90 100% Synthetic Gear Lube

    The most popular AMSOIL gear lube. Outstanding extreme-pressure protection for differentials, transfer cases, and manual transmissions in cars, light trucks, and SUVs. Built-in friction modifiers handle most limited-slip differentials.

    Viscosity:

    75W-90

    Specifications:

    • • API GL-5/MT-1
    • • SAE J2360
    • • Dana SHAES 256 Rev C
    • • Mack GO-J Plus
    • • ZF TE-ML 05A/12L/16F/17B/19C/21A

    Product Code: SVGPK-EA

    Shop Now
    Shop AMSOIL SEVERE GEAR 75W-85 100% Synthetic Gear Lube
    AMSOIL SEVERE GEAR 75W-85 100% Synthetic Gear Lube

    AMSOIL SEVERE GEAR 75W-85 100% Synthetic Gear Lube

    Lower-viscosity SEVERE GEAR formulated for late-model rear differentials and transfer cases that specify a lighter gear oil for improved fuel economy without sacrificing extreme-pressure protection.

    Viscosity:

    75W-85

    Specifications:

    • • API GL-5
    • • Ford XL-1 / WSL-M2C942-A friendly fitments

    Product Code: SVLPK-EA

    Shop Now
    Shop AMSOIL SEVERE GEAR 75W-110 100% Synthetic Gear Lube
    AMSOIL SEVERE GEAR 75W-110 100% Synthetic Gear Lube

    AMSOIL SEVERE GEAR 75W-110 100% Synthetic Gear Lube

    A heavier all-season viscosity for 3/4-ton and 1-ton trucks, heavy towing, and severe-service differentials. Maintains thicker hot-temperature film strength than 75W-90 while still flowing well in winter.

    Viscosity:

    75W-110

    Specifications:

    • • API GL-5/MT-1
    • • Ford WSL-M2C192-A
    • • SAE J2360

    Product Code: SVTPK-EA

    Shop Now
    Shop AMSOIL SEVERE GEAR 75W-140 100% Synthetic Gear Lube
    AMSOIL SEVERE GEAR 75W-140 100% Synthetic Gear Lube

    AMSOIL SEVERE GEAR 75W-140 100% Synthetic Gear Lube

    Maximum hot-temperature protection for the most extreme applications — heavy fifth-wheel and gooseneck towing, commercial hauling, off-road racing, and high-pinion differentials operating at sustained loads.

    Viscosity:

    75W-140

    Specifications:

    • • API GL-5/MT-1
    • • SAE J2360
    • • Ford WSL-M2C192-A
    • • Dana SHAES 256 Rev C

    Product Code: SVOPK-EA

    Shop Now
    Shop 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

    An 80W-90 multigrade synthetic gear lube for older vehicles, trailers, and equipment that originally specified an 80W-90 conventional GL-5. Replaces conventional 80W-90 with synthetic shear stability and oxidation resistance.

    Viscosity:

    80W-90

    Specifications:

    • • API GL-5
    • • MIL-PRF-2105E
    • • SAE J2360

    Product Code: AGLPK-EA

    Shop Now
    Shop AMSOIL SEVERE GEAR SAE 250 100% Synthetic Gear Lube
    AMSOIL SEVERE GEAR SAE 250 100% Synthetic Gear Lube

    AMSOIL SEVERE GEAR SAE 250 100% Synthetic Gear Lube

    Ultra-heavy SAE 250 racing gear lube. Engineered for shock-loaded competition rear ends, drag racing, mud racing, and high-pinion differentials where conventional gear oils sling off and tear under extreme G-forces.

    Viscosity:

    SAE 250

    Specifications:

    • • API GL-5
    • • Built for racing & shock-load applications

    Product Code: SRTQT-EA

    Shop Now

    Long Life

    AMSOIL Long Life 100% Synthetic Gear Lube

    Engineered for extended-drain heavy-duty service — over-the-road tractors, fleet trucks, and commercial axles. Designed to deliver up to 500,000-mile (805,000 km) drain intervals in qualifying linehaul applications, reducing maintenance downtime and total cost of ownership.

    Shop AMSOIL 75W-90 Long Life 100% Synthetic Gear Lube
    AMSOIL 75W-90 Long Life 100% Synthetic Gear Lube

    AMSOIL 75W-90 Long Life 100% Synthetic Gear Lube

    Heavy-duty fleet gear lube engineered for 500,000-mile drain intervals in qualifying over-the-road truck differentials. Outstanding cold-weather pumpability for winter startup and shifting, with exceptional rust, corrosion, and seal protection.

    Viscosity:

    75W-90

    Specifications:

    • • API GL-5
    • • SAE J2360
    • • Mack GO-J Plus
    • • Eaton PS-037
    • • ArvinMeritor O-76-A/B/D/E/J/L/M/N
    • • Dana SHAES 234

    Product Code: FGRQT-EA

    Shop Now
    Shop AMSOIL 80W-140 Long Life 100% Synthetic Gear Lube
    AMSOIL 80W-140 Long Life 100% Synthetic Gear Lube

    AMSOIL 80W-140 Long Life 100% Synthetic Gear Lube

    Heavier 80W-140 viscosity Long Life formulation for extended-drain service in heavy-haul and high-temperature commercial applications. Same 500,000-mile drain capability with extra hot-temperature film strength for severe-duty operation.

    Viscosity:

    80W-140

    Specifications:

    • • API GL-5
    • • SAE J2360
    • • Mack GO-J Plus
    • • Eaton PS-037
    • • ArvinMeritor O-76-N

    Product Code: FGO05-EA

    Shop Now

    Powersports & Marine

    Powersports, Marine & Specialty Gear Oils

    Application-specific gear lubricants for V-Twin motorcycles, ATVs, snowmobiles, and marine outboards/sterndrives. Each fluid is formulated for the unique demands of its drivetrain — wet-clutch primary cases, sealed chaincases, and water-exposed marine lower units.

    Shop AMSOIL 100% Synthetic V-Twin Primary Fluid
    AMSOIL 100% Synthetic V-Twin Primary Fluid

    AMSOIL 100% Synthetic V-Twin Primary Fluid

    Dedicated primary chaincase fluid for Harley-Davidson and other V-Twin motorcycles. Delivers consistent clutch feel, helps prevent clutch slip during hard takeoffs, and protects the compensator bearing, primary chain, and gears against wear.

    Viscosity:

    Primary-spec

    Specifications:

    • • Harley-Davidson primary chaincases
    • • Dedicated wet-clutch chemistry

    Product Code: MVPQT-EA

    Shop Now
    Shop AMSOIL 100% Synthetic Chaincase & Gear Oil
    AMSOIL 100% Synthetic Chaincase & Gear Oil

    AMSOIL 100% Synthetic Chaincase & Gear Oil

    Long-lasting synthetic chaincase oil for ATVs and snowmobiles, including Arctic Cat Diamond Drive gearcases. Extreme-pressure additives extend chain and gear life, with low-temperature fluidity for cold-start efficiency in winter operation.

    Viscosity:

    Chaincase grade

    Specifications:

    • • ATV/snowmobile chaincases
    • • Arctic Cat Diamond Drive gearcases

    Product Code: TCCCN-EA

    Shop Now
    Shop AMSOIL 75W-90 100% Synthetic Marine Gear Lube
    AMSOIL 75W-90 100% Synthetic Marine Gear Lube

    AMSOIL 75W-90 100% Synthetic Marine Gear Lube

    Premium synthetic gear lube for marine outboard and sterndrive lower units. Maintains gear and bearing protection even when contaminated with up to 15% water — critical when seal failure allows water intrusion. Excellent foam control and corrosion protection.

    Viscosity:

    75W-90

    Specifications:

    • • API GL-5
    • • Marine outboard & sterndrive gearcases

    Product Code: AGMPK-EA

    Shop Now

    Additives

    Limited-Slip & Differential Additives

    Friction-modifier additives for clutch-type limited-slip differentials. Required when using a non-LS-formulated gear oil in trucks, performance cars, and SUVs equipped with limited-slip rear ends — eliminates clutch chatter on tight turns and slow-speed maneuvers.

    Shop AMSOIL Slip Lock® Differential Additive
    AMSOIL Slip Lock® Differential Additive

    AMSOIL Slip Lock® Differential Additive

    Advanced friction-modifier additive that eliminates limited-slip gear-housing chatter. Add to any AMSOIL gear lube in clutch-type LSDs found in most pickups, SUVs, and performance vehicles. One 4 oz. tube treats most rear differentials.

    Specifications:

    • • Clutch-type limited-slip differentials
    • • Compatible with all AMSOIL gear lubes
    • • 4 oz. easy-pour tube

    Product Code: ADATB-EA

    Shop Now

    Viscosity Selector

    SEVERE GEAR® Viscosity Guide — Which Gear Lube Do You Need?

    Use this table to match an AMSOIL SEVERE GEAR viscosity to your vehicle and use case. Always confirm against your owner's manual before changing fluid.

    ViscosityBest ForVehicle ExamplesOperating TempSpec
    75W-85Late-model fuel-economy axlesNewer half-ton trucks, SUVs, crossovers spec'ing a thinner gear oil−40°F to 250°FAPI GL-5
    75W-90Most common — daily driving, light towingCars, light trucks, SUVs, Jeeps, transfer cases, manual transmissions−40°F to 300°FAPI GL-5 / MT-1, SAE J2360
    75W-110Heavy half-ton, 3/4-ton trucks, towingPickup differentials under regular trailer load, heat-prone axles−40°F to 325°FAPI GL-5 / MT-1, Ford WSL-M2C192-A
    75W-140Heavy towing, hauling, off-road, racing1-ton diesel trucks, fifth-wheel / gooseneck towing, performance vehicles−40°F to 350°F+API GL-5, SAE J2360
    80W-90Older vehicles, equipment specifying conventional 80W-90Classic trucks, agricultural and industrial equipment−15°F to 300°FAPI GL-5
    SAE 250Drag race, pulling, extreme high-loadRace differentials, transfer cases under sustained extreme load32°F to 400°FAPI GL-5

    Side-by-Side

    SEVERE GEAR® vs. AMSOIL Long Life Gear Lube

    Both are 100% synthetic and built to outperform conventional gear oil — but they're engineered for different jobs. Here's how to choose between them.

    FeatureSEVERE GEAR®Long Life
    Primary applicationCars, light trucks, SUVs, off-road, towingClass 8 over-the-road fleet trucks
    Drain intervalUp to 2× OEM severe-service intervalsUp to 500,000 miles in qualifying linehaul
    Viscosities offered75W-85, 75W-90, 75W-110, 75W-140, 80W-90, SAE 25075W-90, 80W-140
    Limited-slip friction modifierBuilt in — handles most factory LSDsNot formulated for LSDs
    Key OEM specsAPI GL-5/MT-1, SAE J2360, Dana SHAES 256API GL-5, Mack GO-J Plus, Eaton PS-037, ArvinMeritor O-76
    Best forMaximum extreme-pressure protectionMaximum drain-interval extension

    The Complete Guide to AMSOIL Synthetic Gear Lube

    Your differential, transfer case, and manual gearbox are sealed-for-life only in marketing brochures. In reality, gear oil shears, oxidizes, and accumulates wear metal as your vehicle racks up miles — and the harder you drive it, tow with it, or run it off-road, the faster that fluid breaks down. AMSOIL synthetic gear lubes are engineered to outlast and outperform every conventional gear oil on the market, with a lineup that covers everything from a daily-driver crossover to a Class 8 linehaul tractor pulling 80,000 lb across the country.

    SEVERE GEAR® — Built for Trucks, Towing & Off-Road

    SEVERE GEAR is AMSOIL's flagship gear lube line. Six viscosities (75W-85, 75W-90, 75W-110, 75W-140, 80W-90, and SAE 250) cover everything from late-model fuel-economy axles to drag-race rear ends. The proprietary extreme-pressure additive package builds a tenacious film on gear teeth that survives shock loads, sustained towing temperatures above 300°F, and the metal-on-metal pressures that pit and score conventional gear oils into early failure. SEVERE GEAR also contains friction modifiers that handle most factory clutch-type limited-slip differentials without requiring a separate additive.

    Long Life — 500,000-Mile Fleet Service

    For Class 8 over-the-road trucks running predictable linehaul cycles, AMSOIL 75W-90 and 80W-140 Long Life are qualified for drain intervals up to 500,000 miles (805,000 km) in qualifying applications. Built to meet the strictest fleet specs — Mack GO-J Plus, Eaton PS-037, ArvinMeritor O-76, Dana SHAES 234 — Long Life dramatically reduces shop time, used-oil disposal cost, and unscheduled differential service across a fleet.

    Marine Gear Lube — Engineered for Water Contamination

    Marine outboard and sterndrive lower units live underwater. Worn or damaged seals let water enter the gearcase, and conventional gear oils lose their film strength almost immediately when emulsified with water. AMSOIL 75W-90 100% Synthetic Marine Gear Lube is tested to maintain gear and bearing protection with up to 15% water contamination — buying you protection between haul-outs even when a seal starts to weep.

    V-Twin Primary, Chaincase & Slip Lock — Application-Specific Chemistry

    Harley-Davidson primaries, Arctic Cat Diamond Drive gearcases, and clutch-type limited-slip differentials all need fluids built around their unique mechanical demands. AMSOIL V-Twin Primary Fluid delivers consistent wet-clutch feel and easy neutral selection. Synthetic Chaincase & Gear Oil protects ATV and snowmobile chaincases against shock and wear in sub-zero starts. Slip Lock additive eliminates LSD chatter when you need extra friction-modifier headroom.

    Order Direct From an Independent AMSOIL Dealer

    Every product on this page links directly to AMSOIL.com with our dealer code attached. Order at retail, or enroll free in the Preferred Customer program to save 25% on every order with no minimums. Fast shipping from regional warehouses across North America.

    Frequently Asked Questions

    What viscosity AMSOIL gear lube do I need for towing?▾
    For half-ton trucks and SUVs doing occasional towing, SEVERE GEAR 75W-90 (or 75W-85 if your manufacturer specifies a lighter grade) gives excellent protection. For 3/4-ton and 1-ton trucks pulling heavy fifth-wheel or gooseneck trailers, step up to 75W-110 or 75W-140 for thicker hot-temperature film strength. Heavy-haul and commercial drivers running over-the-road should consider AMSOIL Long Life 75W-90 or 80W-140 for extended drain intervals.
    Do I need to add Slip Lock to AMSOIL SEVERE GEAR?▾
    Most clutch-type limited-slip differentials work fine on SEVERE GEAR alone because it already contains friction modifiers. However, if you experience chatter or grabbing during slow turns after a fluid change, add one tube of AMSOIL Slip Lock to restore proper clutch action. Some heavily-worn or aftermarket LSDs require Slip Lock from the start. Always check your service manual.
    How often should I change differential and transfer case fluid?▾
    OEM intervals typically range from 30,000 to 60,000 miles for normal service, dropping to 15,000–30,000 miles for severe service (towing, off-road, dusty conditions). AMSOIL SEVERE GEAR is engineered to safely extend these intervals when used as directed, and AMSOIL Long Life 75W-90 is qualified for up to 500,000 miles in qualifying heavy-duty linehaul service. After deep water fording, change fluid immediately regardless of mileage — water contamination destroys gear oil performance.
    Can I mix AMSOIL gear lube with conventional gear oil?▾
    Yes — AMSOIL synthetic gear lubes are fully compatible with conventional and other synthetic API GL-5 gear oils. Mixing reduces the performance benefits of the AMSOIL fluid, however, so we recommend a complete drain and refill for best results. There's no harm in topping off with AMSOIL between drain intervals if you're low.
    What's the difference between SEVERE GEAR and Long Life?▾
    SEVERE GEAR is engineered for passenger vehicles, light trucks, SUVs, and severe-service applications like towing, off-road, and racing — maximum extreme-pressure protection in viscosities from 75W-85 to SAE 250. Long Life is purpose-built for over-the-road Class 8 fleet trucks needing extended-drain service up to 500,000 miles, formulated to meet Mack GO-J Plus, Eaton PS-037, and ArvinMeritor O-76 specs.
    Why use synthetic gear lube instead of conventional?▾
    Synthetic base oils don't contain the wax, sulfur, and other impurities found in petroleum gear oils, so they flow better in cold weather, resist thermal breakdown at high temperatures, and maintain protective viscosity across a wider operating range. In a differential running 250°F+ under load, conventional 75W-90 thins out and oxidizes — synthetic SEVERE GEAR holds its film and protects the gears.
    Does AMSOIL gear lube work for marine outboards and sterndrives?▾
    Use AMSOIL 75W-90 100% Synthetic Marine Gear Lube — it's formulated specifically for the unique demands of marine lower units, including the ability to maintain gear and bearing protection even when contaminated with up to 15% water from seal weep. Standard automotive SEVERE GEAR is not the right choice for marine gearcases.

    Related Products

    Transmission FluidSynthetic Motor OilDiesel OilGreaseV-Twin Motorcycle Oil

    Ready to Order?

    Shop the full AMSOIL gear lube lineup with your Preferred Customer discount.

    Shop Now Save 25% — Become Preferred Customer