AMSOIL 75W-90 Manual Transmission & Transaxle Gear Lube

Product overview

Manual gearboxes and transaxles that call for a GL-4 gear lube need film strength for the gear teeth without the aggressive additive package used in hypoid axles. AMSOIL 75W-90 Manual Transmission and Transaxle Gear Lube is built for that middle ground.

It pours at -56°C, which matters in a manual box, because cold gear oil is what makes first and second gear feel notchy before the transmission warms up.

Where this fluid fits

Use in applications requiring a 75W-85, 75W-90, or 80W-90 gear oil, including:

• Certain models from Hyundai, Infiniti, Kia, Lexus, Mazda, Mitsubishi, Nissan, Suzuki, Toyota, Volkswagen, and Hino
• Street rod and muscle car transmissions including Muncie, Borg Warner, Saginaw, Ford Toploader, Dearborn, and New Process

Gear lube or synchromesh fluid: the manual gearbox decision

Both fluids go into a manual gearbox, and that is where the similarity ends. AMSOIL 75W-90 Manual Transmission and Transaxle Gear Lube provides a thick lubricating film and carries extreme-pressure additives for gear teeth working under load, which is a different job from the friction control a synchronizer ring needs. The specification list on this page shows the API, Chrysler, ZF, MAN, and Mercedes-Benz requirements this gear lube covers as published.

5W-30 Manual Synchromesh Transmission Fluid covers the opposite case, the transmissions and transaxles built around non-extreme-pressure fluids and factory synchromesh specifications. Swapping one for the other because both belong in a manual gearbox ignores the additive system the box was designed around. The specification in the service literature settles it, never the viscosity on the label.

Manual transmissions and transaxles, not hypoid axles

The published application is manual transmissions and transaxles calling for a 75W-85, 75W-90, or 80W-90 gear oil, which reaches from front-wheel-drive transaxles across a range of import models to street rod and muscle car boxes. Front-wheel-drive service is where the GL-4 performance level earns its keep, since a transaxle packs the gear set and the final drive into a single case and asks one fill to handle both.

Two factory part numbers, GM 12346190 and Chrysler 4874459, are replaced by this lube in NV 4500 service. A hypoid rear axle, by contrast, is a separate decision with its own specification, so a matching grade on two labels is not a reason to run one product in both compartments.

Shock loading from towing and heavy hauling

Towing, heavy hauling, and performance driving load a gearbox in short, hard spikes rather than steady pressure, and heat climbs along with the load. This lube maintains its viscosity despite rigorous mechanical action instead of thinning out, and its extreme-pressure additives are aimed at wear in exactly that kind of severe service. The four-ball wear test (ASTM D4172B at 40 kg, 75°C, 1200 rpm, one hour) produced a 0.40 mm scar.

Heat is the other half of the problem. The New Venture NV-4500 illustrates it well, since the cast-iron housing retains heat and the transmission is often subject to increased torque from turbodiesel engines. Resistance to thermal breakdown and oxidation is what keeps a fill usable there. Heavy-duty highway gearboxes that specify an SAE 50 lubricant take SAE 50 Long-Life Synthetic Transmission Oil instead.

Cold flow, synchronizer engagement, and seal condition

A pour point of -56°C (-69°F) and a viscosity index of 181 keep the lube moving after a night parked outside. The friction-modified formula and its cold-flow properties promote smooth, fast engagement of synchronizers and gears, and the additive package protects brass synchronizers as well as the gear teeth.

Seal conditioners are included to reduce leaks during long storage, which matters for a hot rod or a seasonal truck that sits for months at a time. Rust and corrosion inhibitors work the same shift, protecting the gear set while a vehicle is parked and not only while it is being driven.

Specifications Manual Transmission Gear Lube 75W-90 covers

This gear lube covers applications that require any of the following:

• API GL-4
• Chrysler MS-9070
• ZF TE-ML 02b, 17a
• MAN 341-Z2 (formerly MAN 341 ML)
• MB 235.5

Coverage as published in the AMSOIL data bulletin, checked July 2026. AMSOIL revises coverage when a formula changes, so confirm against AMSOIL's current data bulletin before ordering.

Service life

Under normal operating conditions it lasts two times longer than conventional petroleum GL-4 gear oils.

Where the original equipment manufacturer recommends synthetic oils, follow the manufacturer's drain interval.

Good to know

• Replaces GM part 12346190 and Chrysler part 4874459.

Typical technical properties

Typical properties published by AMSOIL, checked July 2026. These are representative values rather than a specification, and they change when AMSOIL updates a formula.

Package sizes and product codes

Select a product code to open that package size on the AMSOIL product page.

Product documents

AMSOIL publishes the full technical detail for this product in these documents.

• Manual Transmission Gear Lube 75W-90 product data bulletin (PDF)
• Manual Transmission Gear Lube 75W-90 safety data sheet (PDF)

Where to order

Confirm this formula is the match for the vehicle or equipment in the AMSOIL product guides, then order Manual Transmission Gear Lube 75W-90 online. Existing members can sign in to apply the discount automatically.

Details and questions