Red Line MT-90 Synthetic Transmission Gear Oil

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We are excited to now carry Red Line's MT-90 high performance full synthetic gear oil for manual transmissions and transaxles!

We have used Red Line MT-90 gear oil for many years and truly believe it lives up to it's marketing hype. We have seen improved shifting performance with less resistance to gear changes in L-, G-, W-, and R-series 2WD and 4WD Toyota Hilux truck and 4Runner transmissions. BigMike has used MT-90 in his Supercharged Toyota MR2 with a Lotus Exige 6-speed transaxle for nearly a decade and swears by it! We encourage you to check it out for yourself!

Specs include:

  • 75W90 GL-4 Full Synthetic Gear Oil
  • Popular in Nissan, Mazda, Mitsubishi, VW/Audi, Lotus Elise/Exige, Toyota, and Mendeola, for on or off road manual transmission applications
  • Offers quicker shifts from a perfect synchronizer coefficient of friction
  • Safe for brass synchros, as it lacks the reactive sulfurs found in most GL-5 oils that cause damage
  • High performance gear protection and longer synchro life
  • Eliminates notchy shifting, even when cold
  • Satisfies the gear oil viscosity requirements of 75W90, 80W90, 90 and motor oil viscosities of SAE 40, 10W40 and 15W40
  • Recommended for GL-1, GL-3 and GL-4 applications, as well as where most special synchromesh fluids are specified

Special note on synthetic gear oil and rebuilt transmissions:
We recommend first breaking in a rebuilt transmission to at least a minimum of 1,000 miles (preferably 5,000 miles) before switching to a synthetic gear oil. The reason is that these oils are engineered with precise friction modifiers that slow or prevent new synchros from breaking in. Once they are broken in with mineral gear oil then you may switch to synthetic. Look at it this way: A properly cared for transmission is going to last 150,000 miles or more, so waiting an initial 1,000 miles is a drop in the bucket for it's lifetime!

Each bottle contains 1 quart (946 ml). Sold individually.

We also carry these other great Red Line Synthetics

75W90 for Differentials

ShockProof for Heavy Duty Use

Proposition 65 Warning for California Consumers

WARNING: Products we sell can expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to