AMSOIL 5W-30 Manual Synchromesh Transmission Fluid

Product overview

Manual transmissions with brass synchronizers need a fluid that lets the synchro rings grab without chewing them up. AMSOIL 5W-30 Manual Synchromesh Transmission Fluid is formulated for that balance, so the box shifts cleanly cold and stays consistent once it warms up.

Its viscosity index of 196 is the highest in the AMSOIL manual transmission lineup, which means the fluid changes thickness less between a winter start and a hot highway run.

Where this fluid fits

Use in automotive and light-truck manual transmissions and transaxles that require a synchromesh fluid, including:

• New Venture NV T350, NV 1500, NV 2550, NV 3500, NV 3550, and NV 5600
• Tremec T4, T5, T18, T56, and T176
• Tremec TKO500, TKO600, TR 3450, and TR 3550

Synchronizer friction and non-extreme-pressure chemistry

A synchromesh gearbox uses a brass ring to match shaft speeds before the gear teeth engage, so the fluid has to let that ring bite without wearing it away. AMSOIL 5W-30 Manual Synchromesh Transmission Fluid is formulated for manual transmissions and transaxles that specify a non-extreme-pressure fluid, and it protects brass components for smooth synchromesh shift quality. The same additive system guards against corrosion and conditions seals over the life of the fill.

Manual gearboxes specified for a gear lube instead need extreme-pressure additives, which is the job of 75W-90 Manual Transmission and Transaxle Gear Lube. The grade printed on the bottle is not what settles the decision. This 5W-30 answers GM, Chrysler, Honda, Land Rover, MG, Mini Cooper, and Texaco fluid requirements, which is a different list from an API GL-4 gear oil requirement.

Cold shifting and a viscosity index of 196

Shift effort peaks on a cold morning, when thick fluid slows the synchronizer down before the gearbox warms through. This formula is built to improve cold-weather shifting, and it pours at -48°C (-54°F), so it is still moving at startup in an unheated garage. Kinematic viscosity measures 49.4 cSt at 40°C and 10.1 cSt at 100°C.

A viscosity index of 196 describes how little the fluid thickens or thins between those two reference temperatures, and gear and bearing protection holds from -40°F (-40°C) to 300°F (149°C). Resisting the thinning effect of mechanical action keeps film strength and anti-wear performance steady rather than fading part way through the interval, and the formula also resists heat, oxidation, acid buildup, and varnish deposits.

Replacing several factory-branded synchromesh fluids

Several vehicle manufacturers sell a branded fluid for their own gearboxes, and stocking each one separately gets expensive. This formula serves as a lower-cost replacement for MTF-94 fluid in Land Rover, MG, and Mini Cooper applications, for Honda Genuine MTF fluid in manual transaxles, and for Shell or Texaco MTX fluid.

For a shop working across mixed makes, one fluid that covers New Venture and Tremec gearboxes alongside GM and Chrysler requirements cuts the number of part numbers on the shelf. That versatility is a stocking convenience, not a reason to skip checking the specification a given gearbox calls for.

Compartments this fluid is not made for

The exclusions are specific and worth reading before the drain plug comes out: no engines, no hypoid rear axles, no limited-slip applications, and no wet-clutch applications. A powersports gearbox that shares its oil with a wet clutch needs a fluid formulated for clutch friction, such as Dirt Bike Transmission Fluid, and a hypoid axle follows whatever gear oil specification the axle itself carries.

Specifications Manual Synchromesh 5W-30 covers

This fluid covers applications that require any of the following:

• GM 9985648, 9986105, 9985535
• Chrysler MS-9224, MS-9417
• Honda Genuine MTF fluid for transaxles
• Land Rover, MG, and Mini Cooper MTF-94
• Texaco MTX fluid

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

Recommended for 50,000-mile service intervals or longer, up to 150,000 miles, as indicated in the owner's manual.

Good to know

• Not for use in engines, hypoid rear axles, limited-slip applications, or wet-clutch applications.

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 Synchromesh 5W-30 product data bulletin (PDF)
• Manual Synchromesh 5W-30 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 Synchromesh 5W-30 online. Existing members can sign in to apply the discount automatically.

Details and questions