Extended-drain lubricant engineered to last longer and protect gears better than conventional gear oils. Reduces wear, conditions seals, and helps prevent rust. Promotes longer equipment life and reduced maintenance costs.
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Product data sheets
View, download, or save a copy of the Product Data Sheet or Safety Data Sheet for AMSOIL 75W-90 Long Life 100% Synthetic Gear Lube.
AMSOIL 75W-90 Long-Life 100% Synthetic Gear Lube (FGR) is the heavy-duty, extended-drain gear oil engineered for 500,000-mile (805,000 km) service life in over-the-road Class 8 trucks, drive axles, trailer axles, and commercial gear applications. Built on premium synthetic base oils with a high-performance additive system, the formula carries API GL-5 and MT-1, MIL-PRF-2105E, plus heavy-duty axle approvals from Dana SHAES 234 (formerly Eaton PS-037), Dana SHAES 256 (formerly Eaton PS-163), Dana SHAES 429A, Mack GO-J and GO-J+, Meritor 0-76N, and ZF TE-ML 07A and 08. It is the long-haul fleet counterpart to AMSOIL Severe Gear 75W-90, formulated for fleet drain intervals and high-load gear and bearing protection.
Long service life in heavy-duty axles
Premium synthetic base oils and a high-performance additive package resist oxidative breakdown so the lubricant stays in service longer than conventional gear oils. The 75W-90 grade is engineered for extended drain intervals up to 500,000 miles (805,000 km) as set by equipment manufacturers for over-the-road trucks and heavy equipment. In passenger cars and light trucks the same formula supports the long drain intervals listed in the service-interval table below, and lasts several times longer than conventional lubricants for less downtime and lower maintenance cost.
High-load gear and bearing wear protection
A shear-stable formulation resists viscosity loss from mechanical activity, so the oil keeps its working film thickness across long pulls, heavy hauls, and high gear-tooth loads in hypoid drive axles. A durable protective film between metal surfaces guards against metal-to-metal contact, and the synthetic base oils combined with anti-wear and extreme-pressure additives resist chemical breakdown for long-lasting protection of ring-and-pinion sets, bearings, and synchros where applicable.
Cold-weather fluidity and all-season performance
The 75W-90 grade pours to -48 C (-54 F) and holds a Brookfield viscosity of 109,000 cP at -40 C (ASTM D2983), so the oil flows to gears and bearings during cold-morning startup instead of forcing the driveline to spin a frozen lube through the housing. Improved cold-temperature fluidity reduces energy lost to friction and helps maximize fuel economy, while a high viscosity index of 143 (ASTM D2270) and a flash point of 208 C (406 F) keep the film stable at the high sump temperatures that develop in long-haul service.
Cleanliness, corrosion control, and seal compatibility
The additive system resists acid build-up to keep gear surfaces clean and efficient over long drains, and posts a 1B rating in the Copper Strip Corrosion Test (ASTM D130) at 121 C for 3 hours. Foam control is rated 0/0, 0/0, 0/0 in ASTM D892, which protects film integrity under the churning action of high-speed gear sets. The formula conditions seals to help prevent leaks and supports rust and corrosion protection for equipment that sees seasonal storage, humid climates, or wet operating environments.
Recommended applications and service intervals
The 75W-90 grade is recommended for over-the-road trucks, light, medium, and heavy-duty trucks, off-road equipment, commercial vehicles, motorhomes, autos, SUVs, emergency vehicles, buses, delivery and utility vehicles, and tractors, plus differentials, manual transmissions, and other gear applications that call for the listed standards. The service-life table from the Data Bulletin is reproduced below.
Cars, SUVs, and light trucks: drain at 100,000 miles of service or according to the owner's manual under normal service, and 50,000 miles or owner's manual under severe service, whichever is longer.
Heavy-Duty Class 8 line haul: follow the OEM drain interval (miles or hours) up to 500,000 miles or five years, whichever comes first.
Vocational and delivery: follow the OEM drain interval (miles or hours) for synthetic oil up to 120,000 miles or three years, whichever comes first. Heavy-duty off-road: follow the OEM drain interval (miles or hours) for synthetic oil up to 100,000 miles or two years, whichever comes first.
For non-differential applications, use the OEM normal or severe synthetic-oil service interval. Where service intervals are unavailable, drain at twice the conventional-oil interval. Extended drain intervals are not supported where water contamination occurs, and gear oils should be changed more frequently in dusty or dirty conditions unless the gear system is properly sealed and equipped with membrane-type breathers.
The 75W-90 grade replaces competitors' 75W-90 and 80W-90 viscosity grades and is compatible with other synthetic and conventional gear oils, although mixing shortens oil life, reduces performance benefits, and voids the extended-drain claim. The formula is compatible with most limited-slip differentials; if limited-slip chatter occurs, add AMSOIL Slip-Lock friction modifier additive.
Typical technical properties
Property
Value
Kinematic Viscosity at 100 C, cSt (ASTM D445)
15.7
Kinematic Viscosity at 40 C, cSt (ASTM D445)
115.8
Viscosity Index (ASTM D2270)
143
Brookfield Viscosity, cP at -40 C (ASTM D2983)
109,000
Flash Point, C (F) (ASTM D92)
208 (406)
Pour Point, C (F) (ASTM D97)
-48 (-54)
Copper Strip Corrosion at 121 C / 3 hr (ASTM D130)
1B
Foam Stability (ASTM D892)
0/0, 0/0, 0/0
Order AMSOIL 75W-90 Long-Life Synthetic Gear Lube
AMSOIL 75W-90 Long-Life Synthetic Gear Lube is available in quart bottle (FGRQT-EA), case of 12 quarts (FGRQT-CA), gallon jug (FGR1G-EA), 5-gallon pail (FGR05-EA), 16-gallon keg (FGR16-EA), 55-gallon drum (FGR55-EA), and 275-gallon tote (FGR27-EA). 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. Match the right product with the AMSOIL Vehicle Lookup Guide, compare grades and OEM specs in the AMSOIL 75W-90 Gear Oil Guide, then order AMSOIL 75W-90 Long-Life 100% Synthetic Gear Lube.
What is the difference between AMSOIL 75W-90 Long-Life Gear Lube (FGR) and Severe Gear 75W-90 (SVG)?
FGR is the fleet, over-the-road, and heavy-duty extended-drain 75W-90, engineered for 500,000-mile service life in Class 8 line-haul axles and built around the Dana SHAES 234 (formerly Eaton PS-037), Dana SHAES 256 (formerly Eaton PS-163), Mack GO-J and GO-J+, and Meritor 0-76N approvals. Severe Gear 75W-90 is the passenger and light-truck severe-service formula for racing, towing, plowing, hauling, and high-temperature differential use. Both meet API GL-5, but FGR is the right choice for heavy-duty drive axles and trailer axles where long fleet drain intervals are required.
Which OEM specifications and standards does the 75W-90 grade meet?
The 75W-90 grade meets API GL-5 and MT-1, MIL-PRF-2105E, Dana SHAES 234 (formerly Eaton PS-037) for 250,000 miles, Dana SHAES 256 (formerly Eaton PS-163) for 500,000 miles, Dana SHAES 429A, Mack GO-J and GO-J+, Meritor 0-76N (75W-90), plus hypoid gear oil specifications from ZF TE-ML 07A and 08, and foreign and domestic OEMs including GM, Ford, and Daimler Chrysler. It can also be used in rear axles where an API GL-4 lubricant is recommended.
How long can the gear oil stay in service?
In Heavy-Duty Class 8 line-haul service, drain at the OEM interval (miles or hours) up to 500,000 miles or five years, whichever comes first. In vocational and delivery service, drain at the OEM synthetic-oil interval up to 120,000 miles or three years. Heavy-duty off-road service is capped at 100,000 miles or two years on the OEM synthetic-oil interval. Cars, SUVs, and light trucks drain at 100,000 miles in normal service or 50,000 miles in severe service, or per the owner's manual, whichever is longer. Extended drain intervals are not supported where water contamination occurs.
Can the 75W-90 replace an 80W-90 conventional gear oil?
Yes. The 75W-90 Long-Life Synthetic Gear Lube replaces competitors' 75W-90 and 80W-90 viscosity grades. The synthetic 75W-90 keeps the cold-temperature fluidity needed for cold-morning startup and the high-temperature stability needed for long pulls, so a single grade covers seasonal use that previously required two conventional grades.
Is the formula compatible with limited-slip differentials?
The 75W-90 is compatible with most limited-slip differentials. If limited-slip chatter occurs after a fluid change, add AMSOIL Slip-Lock friction modifier additive to restore the friction characteristics required by the clutch packs.
Will running this gear lube void a heavy-duty truck or axle warranty?
No. Using AMSOIL synthetic lubricants and practicing the listed drain intervals does not void a new vehicle or equipment manufacturer warranty, and the product is backed by the AMSOIL Limited Warranty. Mixing with other gear oils, however, will shorten oil life and the extended-drain claim is not supported when oils have been mixed.
