AMSOIL guide
AMSOIL 75W-90 Gear Oil Guide
AMSOIL SEVERE GEAR 75W-90 (SVG) is the standard pick for modern hypoid differentials, transfer cases, and ATV/UTV axles in cars, light trucks, SUVs, and powersports machines. It is full synthetic, API GL-5, and engineered for the heavy gear shock and sustained high-load operation a hypoid final drive sees in towing, hauling, plowing, and off-road service. The GL-4 vs GL-5 rule still applies: SEVERE GEAR is GL-5 and belongs in differentials and transfer cases, not in manual gearboxes with brass synchros.
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AMSOIL SEVERE GEAR 75W-90 spec at a glance
| Spec | Value |
|---|---|
| API category | GL-5 |
| SAE viscosity | 75W-90 |
| Base stock | 100% synthetic |
| Drain interval (normal service) | Up to 100,000 mi |
| Drain interval (severe service) | Up to 50,000 mi |
| Limited-slip compatibility | Yes (factory friction modifier; add Slip Lock for chatter) |
| Where to buy | Buy online | Product details |
Where AMSOIL SEVERE GEAR 75W-90 fits
SEVERE GEAR 75W-90 covers the bulk of modern hypoid differential and transfer-case applications. The light-truck and SUV side includes most current Ford F-150 and F-250 (front diff and rear diff where 75W-90 is spec'd), GM Silverado 1500 (most rear diffs), Ram 1500 (most differential applications), and the front and rear differentials on Toyota Tundra, Tacoma, 4Runner, and Land Cruiser.
The powersports side includes the front and rear differentials on Polaris Sportsman and Ranger, Honda Foreman/Rancher (where 75W-90 is spec'd), Yamaha Grizzly and Kodiak, Kawasaki Brute Force, Suzuki KingQuad, and Can-Am Outlander/Defender. Confirm the spec'd viscosity against the owner's manual; some applications call for 80W-90 (see the 80W-90 gear oil guide) or a heavier 75W-110 or 75W-140.
GL-4 vs GL-5: why SEVERE GEAR is not for manual transmissions
API GL-5 uses a higher-EP sulfur-phosphorus additive package than API GL-4. The extra EP protection is exactly what a hypoid differential needs to handle the sliding-tooth contact pattern hypoid gears use. The same additive package is corrosive to the brass and bronze synchros in most manual transmissions, so SEVERE GEAR 75W-90 (GL-5) does not belong in a manual gearbox even if the SAE viscosity matches.
For European 75W-90 GL-4 manual transaxles (VW, BMW, Mini, Volvo), use AMSOIL Synthetic Manual Transmission & Transaxle Gear Oil 75W-90 (MTG) instead. The full breakdown lives in the manual transmission fluid guide.
Limited-slip differentials and AMSOIL Slip Lock
SEVERE GEAR 75W-90 contains friction modifiers compatible with most limited-slip clutch packs. For LSDs that specifically call for an additional friction modifier (chatter on tight turns is the symptom), AMSOIL Slip Lock Friction Modifier is the matched additive. The Ford 9.75 inch rear, GM Eaton G80, and many Yamaha and Honda ATV LSDs benefit from the extra modifier dose.
Bottom line: when should you use AMSOIL SEVERE GEAR 75W-90?
- Modern light-truck or SUV hypoid differential. Pick AMSOIL SEVERE GEAR 75W-90 (also online from AMSOIL).
- Transfer case calling for 75W-90 GL-5. Same product.
- ATV or UTV front/rear differential calling for 75W-90. Same product; see the ATV oil guide.
- Warm-climate classic or muscle car. Use SEVERE GEAR 80W-90 instead; see the 80W-90 guide.
- European GL-4 manual transaxle. Use AMSOIL Synthetic MTG 75W-90; see the manual transmission fluid guide.
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AMSOIL Preferred Customer membership is $20 USD per year ($10 USD for a six-month trial) and unlocks up to 25% off on every product, with free shipping on qualifying orders. Add the membership to the same cart as your order and qualifying products switch to member pricing on that checkout, with no separate sign-up step. See the breakdown on the AMSOIL Preferred Customer page, or sign up directly through the AMSOIL Preferred Customer enrollment page.
AMSOIL 75W-90 gear oil FAQ
Is 75W-90 the same as 80W-90?
They share the same 90 high-temperature grade. The 75W cold-cranking grade flows faster at startup than 80W. For cold-climate operation, towing applications with cold morning starts, or any modern light-truck/SUV differential that calls for 75W-90, pick 75W-90. For warm-climate classics or older trucks specifically spec'd for 80W-90, use 80W-90; see the 80W-90 gear oil guide.
Does AMSOIL SEVERE GEAR work in limited-slip differentials?
Yes. AMSOIL SEVERE GEAR 75W-90 contains friction modifiers compatible with most limited-slip clutch packs. For LSDs that specifically call for an additional friction modifier (clutch chatter on tight turns is the symptom), add AMSOIL Slip Lock Friction Modifier per the OEM specification.
What about a 75W-90 GL-4 manual transaxle?
Some European manual transaxles (VW, BMW, Mini, Volvo) specifically call for 75W-90 GL-4, not GL-5. Use AMSOIL Synthetic Manual Transmission & Transaxle Gear Oil 75W-90 (MTG) for those applications. Putting a GL-5 oil in a GL-4 transaxle corrodes the synchros. See the manual transmission fluid guide.
How long does AMSOIL SEVERE GEAR last?
Up to 100,000 miles in normal service in cars and light trucks, and up to 50,000 miles in severe service (towing, hauling, plowing, off-road). These are AMSOIL's published guidelines; verify against your specific application and OEM warranty terms.
Is SEVERE GEAR 75W-90 safe in an ATV or UTV differential?
Yes. SEVERE GEAR 75W-90 is the standard pick for ATV and UTV front and rear differentials that call for 75W-90. See the ATV oil guide for the full powersports drivetrain lineup.
Where do I buy AMSOIL 75W-90 gear oil?
Order online from AMSOIL on the SEVERE GEAR 75W-90 product page. Browse the full gear oil family on AMSOIL's gear oil page, and the matching gear lubricants overview.
Order AMSOIL SEVERE GEAR 75W-90
Order online from AMSOIL's SEVERE GEAR 75W-90 product page. To unlock up to 25% off, add an AMSOIL Preferred Customer membership to the same cart and qualifying products switch to member pricing immediately, with no separate sign-up step.