AMSOIL 75W-90 Synthetic Manual Transmission and Transaxle Gear Lube delivers smooth shifts and outstanding extreme-pressure protection. It suits a wide range of import, domestic, and classic muscle-car gearboxes that call for 75W-85, 75W-90, or 80W-90 gear lube.
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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 Manual Transmission & Transaxle Gear Lube.
AMSOIL 75W-90 Synthetic Manual Transmission and Transaxle Gear Lube
AMSOIL 75W-90 Synthetic Manual Transmission and Transaxle Gear Lube is a 100 percent synthetic API GL-4 gear oil engineered for manual gearboxes and front-wheel-drive transaxles that specify a 75W-85, 75W-90, or 80W-90 viscosity. Sold under product code MTG, the formula is built around the shock-loading, heat soak, and synchronizer engagement found in the New Venture NV-4500 transmission, Mazda Miata MX-5 transaxle, and a long list of import GL-4 manual gearboxes.
Wear and shock-load protection in severe service
The fluid is shear-stable and holds its viscosity grade despite the rigorous mechanical action of a synchromesh gearbox. A thick lubricating film paired with extreme-pressure additives protects gear teeth, bearings, and synchronizer faces during shock-loading conditions common to towing, heavy hauling, and high-torque turbodiesel pickups. Four-Ball Wear performance is rated at a 0.40 mm scar based on independent testing per ASTM D4172B at 40 kg, 75 C, 1200 rpm, 1 hour, which represents strong boundary protection for an API GL-4 lubricant.
Quick, smooth shifts on synchronizer-equipped boxes
The friction-modified additive package is tuned for fast, clean engagement of brass and bronze synchronizers without the slip-through or notchy lockout that high-extreme-pressure GL-5 differential oils can cause in a manual transmission. Cold-flow performance carries that shift quality into morning starts and winter operation, and the formula includes seal conditioners that help keep input and output shaft seals pliable, reducing the slow drips common to hot rods, restored muscle cars, and weekend drivers that sit between trips.
Cold-flow and high-temperature viscosity stability
A viscosity index of 181 by ASTM D2270 keeps the oil from thinning excessively at gearbox operating temperatures or thickening into a no-flow gel during cold starts. Pour point is rated at minus 56 C (minus 69 F) by ASTM D97, so the lube continues to circulate to upper gears and synchronizers in cold-climate driving. On the hot end, a flash point of 226 C (439 F) by ASTM D92 supports stable performance in heat-soaked applications such as the cast-iron NV-4500, which retains heat and is often paired with high-torque turbodiesel engines.
API GL-4 longevity for front-wheel-drive transaxles
Front-wheel-drive transaxles run the manual gearset, differential, and synchronizers in a single shared sump that operates hotter and at lower fluid volume than a split gearbox-and-axle layout. AMSOIL 75W-90 Synthetic Manual Transmission and Transaxle Gear Lube exceeds API GL-4 performance requirements and resists thermal degradation and oxidation, which helps keep gear coatings intact, brass synchronizers from etching, and rebuild intervals in the planned-service column for daily-driven Hyundai, Toyota, and Volkswagen transaxles.
OEM specifications and crossover coverage
The formula meets API GL-4 plus a stack of OEM and tier-one specifications: ZF TE-ML 02B, 16A, 17A, and 19A; Chrysler MS-9070; MAN 341-Z2 (formerly MAN 341 ML); and Mercedes-Benz 235.5. It serves as a crossover for GM part 12346190 and Chrysler part 4874459 in NV-4500 service. Factory-fill applications calling for a 75W-90 GL-4 lubricant include certain models from Hyundai, Infiniti, Kia, Lexus, Mazda, Mitsubishi, Nissan, Suzuki, Toyota, Volkswagen, and Hino. Street-rod and muscle-car gearboxes covered include Muncie, Borg Warner, Saginaw, Ford Toploader, Dearborn, and New Process designs.
Recommended applications and service intervals
Use this gear lube in manual transmissions and transaxles that specify a 75W-85, 75W-90, or 80W-90 viscosity gear oil with any of the listed approvals. The product is built for the API GL-4 side of the manual-transmission lubricant family, not for hypoid differentials that call for a GL-5 oil; for differentials, rear axles, and limited-slip service, AMSOIL Severe Gear 75W-90 is the correct selection. Confirm vehicle application match with the AMSOIL Vehicle Lookup Guide and the AMSOIL 75W-90 Gear Oil Guide.
Normal service: under typical operating conditions, this synthetic GL-4 gear oil lasts two times longer than conventional petroleum GL-4 gear oils.
OEM-synthetic service: where the original equipment manufacturer specifies synthetic oils, follow the OEM drain interval, including the New Venture NV-4500 transmission schedule.
Exclusions: not intended for hypoid differentials or rear axles requiring API GL-5, for automatic transmissions, or for transfer cases that specify a dedicated transfer-case fluid or automatic transmission fluid.
Outside the United States and Canada: confirm the local OEM gear-lube specification before changing fluid; the product is approved against the listed European and Asian specs above.
Refill volume should come from the gearbox service manual. AMSOIL gear lubes do not require aftermarket additives, slip modifiers, or break-in supplements, and mixing with conventional or other synthetic GL-4 fluids shortens service life and dilutes shear stability.
Typical technical properties
Property
Value
Kinematic Viscosity at 100 C, cSt (ASTM D445)
14.0
Kinematic Viscosity at 40 C, cSt (ASTM D445)
80.3
Viscosity Index (ASTM D2270)
181
Flash Point, C (F) (ASTM D92)
226 (439)
Pour Point, C (F) (ASTM D97)
-56 (-69)
Four-Ball Wear (ASTM D4172B at 40 kg, 75 C, 1200 rpm, 1 hr), Scar, mm
0.40
Order AMSOIL 75W-90 Synthetic Manual Transmission and Transaxle Gear Lube
Available sizes include the Quart Easy-Pack (MTGPK-EA single, MTGPK-CA case of 12), Quart bottle (MTGQT-EA single, MTGQT-CA case of 12), 5-gallon pail (MTG05-EA), and 55-gallon drum (MTG55-EA). Every package is backed by the AMSOIL Limited Warranty. Match the right grade to the gearbox with the AMSOIL Vehicle Lookup Guide and confirm GL-4 versus GL-5 selection in the AMSOIL 75W-90 Gear Oil Guide before ordering. Order Now.
I've enjoyed the stuff ever since the first time I bought a case of it down in Daytona Beach at Bike Week it made my Harley run cooler I saw loads of different big time change and Improvement in my Harley ever since then I've been addicted to the Anvil products this product in particular I enjoyed my transmission and I plan on doing an oil change in my Jeep very soon
By CHAngo on July 05, 2026.
Would recommend this to a friend.
Made my 87 Porsche 924s like new
I thought the transaxle was going out on me. I inspected the clutch and it was fine. I switched to a better quality fluid, this stuff, and that did it. I think I was loosing horsepower or gears weren't engaging properly before. What a difference the proper fluid makes! Shifts are crisp, engagement is solid. I was missing out this entire time.
By Richard from Ontario, California on April 30, 2026.
Is MTG the same product as AMSOIL Severe Gear 75W-90?
No. AMSOIL Severe Gear 75W-90 is an API GL-5 hypoid axle and differential lubricant. AMSOIL 75W-90 Synthetic Manual Transmission and Transaxle Gear Lube (MTG) is an API GL-4 fluid built for synchronizer-equipped manual gearboxes and front-wheel-drive transaxles. The two oils are not interchangeable; running a GL-5 differential oil in a GL-4 manual transmission can attack brass and bronze synchronizers and dull shift quality.
Will this gear lube work in a Mazda Miata MX-5 manual transaxle?
Yes for Miata generations that specify a 75W-90 API GL-4 gear oil for the manual transaxle. The formula meets the GL-4 performance and 75W-90 viscosity requirement common to those gearboxes and is friction-modified for synchromesh service. Confirm the exact factory fluid spec with the owner manual or the AMSOIL Vehicle Lookup Guide before changing fluid.
Does this oil meet API GL-4, GL-5, or both?
The bulletin specification is API GL-4. Manual transmissions and transaxles built around brass or bronze synchronizers are designed for the GL-4 additive chemistry, which is what this product delivers. Hypoid differentials, limited-slip axles, and most rear-drive truck axles call for a GL-5 lubricant such as AMSOIL Severe Gear instead.
What manual transmissions and transaxles is this gear lube intended for?
Applications include the New Venture NV-4500 (replacing GM part 12346190 and Chrysler part 4874459) and certain manual gearboxes and transaxles from Hyundai, Infiniti, Kia, Lexus, Mazda, Mitsubishi, Nissan, Suzuki, Toyota, Volkswagen, and Hino. Muscle-car and street-rod transmissions covered include Muncie, Borg Warner, Saginaw, Ford Toploader, Dearborn, and New Process designs that specify a 75W-85, 75W-90, or 80W-90 GL-4 lubricant.
How long can MTG stay in service?
Under normal operating conditions, the product lasts two times longer than conventional petroleum GL-4 gear oils. Where the original equipment manufacturer specifies synthetic oils, follow the OEM drain interval, such as the NV-4500 transmission service schedule. Severe-duty work, racing, or sustained shock-loading should be governed by gearbox temperature and used-oil analysis rather than time alone.
Can MTG be mixed with conventional or other synthetic GL-4 fluids?
The formula is compatible with conventional and other synthetic GL-4 gear oils for top-off purposes, but mixing dilutes shear stability and friction modification and shortens service life. A full drain and refill is the right approach when switching fluids, and aftermarket gear-oil additives, friction modifiers, and slip enhancers are not recommended.
Does using AMSOIL gear lube void a new-vehicle warranty?
No. Using AMSOIL synthetic lubricants does not void a new-vehicle or new-equipment manufacturer warranty, and the product itself is backed by the AMSOIL Limited Warranty.
