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

Available sizes

AMSOIL Severe Gear 75W-140 100% Synthetic Gear Lube

AMSOIL Severe Gear 75W-140 100% Synthetic Gear Lube (SVO) is a premium-grade, heavy-viscosity extreme-pressure synthetic gear oil engineered for the rear differentials and gearsets that take the hardest hits. Built on synthetic base oils with a proprietary extreme-pressure additive package, the formula meets API GL-5 and 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. The 75W-140 grade is the right choice when an OEM specifies a heavy-viscosity GL-5 lubricant for differentials in HD pickups, RV chassis, tow rigs, fleet trucks, and equipment running under towing, hauling, plowing, racing, and high ambient temperature loads.

Maximum wear protection under shock load

Heavy towing, sudden throttle, and steep grades drive shock loads into the ring and pinion. The 75W-140 formula is engineered for severe-duty service and maintains viscosity under these conditions to keep a protective film between gear teeth. Proprietary additives form an iron-sulfide barrier coating on gear surfaces, defending against wear, pitting, and scoring when the lubricant film is at its thinnest.

Controls thermal runaway in differentials

Thermal runaway happens when a gear lubricant cannot keep friction in check, heat climbs, viscosity drops further, and oil oxidation accelerates in a self-feeding cycle. Severe Gear 75W-140 is built to interrupt that cycle. The synthetic base stocks resist breakdown from sustained high heat, and the additive system controls friction so operating temperatures stay lower under load. Inhibiting rapid lubricant degradation extends oil, seal, and component life on tow rigs and equipment that work hard for long stretches.

Cold-flow performance and shifting feel

Wax-free synthetic construction keeps the lube fluid in deep cold, improving cold-flow properties and cold-weather shifting. The 75W-140 grade reaches a Brookfield viscosity of 109,000 cP at -40 C (ASTM D2983) and a pour point of -43 C (ASTM D97), so circulation begins faster on a cold start and gear teeth see a continuous film sooner.

Heavy-viscosity stability for high film strength

The 75W-140 grade carries a kinematic viscosity of 25.9 cSt at 100 C (ASTM D445) and 172.1 cSt at 40 C (ASTM D445), with a viscosity index of 186 (ASTM D2270). That heavy 140 backbone is built for high-load, high-temperature differential service where a lighter 75W-90 thins out: extended towing, plowing, off-road work, and racing.

Rust, corrosion, and limited-slip compatibility

Differentials sit at the bottom of the drivetrain and collect moisture, road spray, and condensation between drives. Severe Gear 75W-140 protects against rust and corrosion on bearings, shafts, and the ring and pinion, and posts a 1b rating on the ASTM D130 copper corrosion test at 121 C. Friction modifiers in the formula make it compatible with most factory limited-slip differentials. Where additional limited-slip friction modifier is required by the OEM, AMSOIL Slip Lock can be added.

Recommended applications and service intervals

Severe Gear 75W-140 (SVO) is built for differentials, manual transmissions, and other gear applications that specify a heavy GL-5 / MT-1 / MIL-PRF-2105E lubricant in the 75W-140 grade, including HD diesel pickups (3/4 ton and 1 ton), HD SUVs, RV chassis and tow rigs, fleet trucks, tow trucks, race cars, tractors, and motor homes operating under any of the following severe conditions:

• Cars, SUVs, and light trucks (differentials): up to 100,000 miles (161,000 km) under normal service or per the owner's manual, whichever is longer; 50,000 miles (80,500 km) under severe service or per the owner's manual, whichever is longer.
• Heavy-duty Class 8 line haul: follow the OEM synthetic-oil drain interval up to 250,000 miles (402,500 km) or three years, whichever comes first. Vocational/delivery: up to 120,000 miles (193,200 km) or three years. Heavy-duty off-road: up to 100,000 miles or two years.
• Manual transmissions and other non-differential gear applications: follow the OEM synthetic interval. Where one is not published, drain at twice the interval listed for conventional oil.
• Severe-duty exclusions: extended drain intervals are not supported when water contamination is possible. Inspect and service the gear oil more frequently in dusty or dirty conditions unless the gear system is sealed and equipped with membrane-type breathers.

The formula 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 gear oil additives other than those specified by AMSOIL are not recommended. Confirm the correct viscosity and GL-5 specification for the rear axle, transfer case, or manual gearbox in question with the AMSOIL Vehicle Lookup Guide before changing fluid.

Typical technical properties

Order Severe Gear 75W-140 Synthetic Gear Lube

Severe Gear 75W-140 Synthetic Gear Lube is available in flexible quart Easy-Pack (SVOPK-EA), quart bottle (SVOQT-EA), case of 12 quart Easy-Packs, 5 gallon pail, 16 gallon keg, 55 gallon drum, and 275 gallon tote sizes. Using AMSOIL synthetic lubricants and practicing extended drain intervals does not void a new vehicle or equipment manufacturer warranty, and all AMSOIL lubricants are covered by the AMSOIL Limited Warranty. Match the right gear oil viscosity and GL-5 spec with the AMSOIL 75W-90 Gear Oil Guide, confirm rear-axle, transfer-case, and manual-gearbox application match in the AMSOIL Vehicle Lookup Guide, then order AMSOIL Severe Gear 75W-140 100% Synthetic Gear Lube.

Frequently asked questions