Red Line 50304 MT-90 75W-90 GL-4 Manual Transmission and Transaxle Lubricant (MTL) - 1 Quart (2 Pack)

Redline lubricants are a premium synthetic oil product for your automobile needs. I utilize it in my classic Alfa Romeo Manual Transmission. Redline surpasses anything that was available when my Alfa was new. It really clings to the gears and shifts effortlessly with no grinding. This product works for most manual gear boxes but always verify with your owners manual. Larry Hunt

I bought a used 2007 Pontiac Vibe in 2021 with 140k miles, it always had a slight grind in the 5 speed transmission, when shifting into 3rd gear, the previous owner took good care of the car with all receipts of everything that had been done to the car, only problem was, when they changed the transmission oil they put GL-5 in it, I had read that others had the same problem, and after doing a lot of research on it, I thought what do II have to lose, after putting MT-90 75W-90 oil in it it stopped grinding almost instantly, smooth the shifts out in all gears and no more grinding in 3rd gear, I have to admit I was skeptical, that it would work, but it made a believer out of me !!! Redline makes a good product !!

I have been using Redline MT90 in my transfer case for around 50k miles now. This case requires GL4 gear oil and the MT90 provides the best shifting and smoothness. I use this in a weekend offroad vehicle so it sees some abuse and I have had zero issues running the gear oil. One of the only true GL4 oil left that I have found. Most others are GL4/5 which doesnt work great with copper synchros.

I've now used this oil in two different manual transmissions used in racing applications. One is a A833 4-speed and the other a Getrag 240/5. This oil quieted the Getrag down at least 50%! Shifts are noticeably smoother and quicker to synchronize. The A833 is used in endurance racing and had no oil issues the entire time.

For Vintage transmissions such as the 1991 Toyota Celica GT-S S53 transmissions, do not use API Gl-5 gear oil. Only use API Gl-4. My rebuilt transmission had Gl-5 and was giving me problems: Excerpts from AI: Type: API GL-4 (Strictly recommended) • ⚠️ WARNING: Do NOT use "GL-5" or "GL-4/GL-5 Compatible" generic gear oils found at most auto parts stores (like Mobil 1 LS). The high sulfur additives in GL-5 attack the brass synchros in Toyota transmissions, causing notchy shifting and premature wear. • Top Recommendations: • Redline MT-90 (The "gold standard" for this transmission) • Amsoil Manual Transmission & Transaxle Gear Lube 75W-90 • Toyota Genuine Manual Transmission Gear Oil (GL-4) 1. The "Washing" Phase The reason it feels like it is "getting smoother" mile by mile is that the Red Line MT-90 is actively scrubbing the old GL-5 film off the synchronizers. • The GL-5 Film: Remember, that Mobil 1 stuff was "too slippery." It left a slick coating on the brass rings. • The New Friction: Every time you shift now, the fresh MT-90 is displacing that old slippery film. The more you shift, the more "bite" the brass gets back. It will likely keep getting better for the next 50–100 miles. Also added was the Redline lightweight "Shockproof.” Why, because I have a slight internal bearing noise, and could be related the wrong API Gl-5 gear oil. After adding, the slight bearing noise appears to be gone.. But that’s another review.

Great stuff. Smoothed my shifting out in my 2007 fj cruiser.

5 star only because it got here quick and was priced well. Been to lazy to work on car. Will update when I decide to do something.

I looked everywhere for transmission fluid for my 2008 Toyota matrix standard 5 speed, you can't find G4 rated fluid anywhere around here, someone told me about this stuff so I decided to give it a try, I got the fluid changed today and It definitely feels like it's shifting smoother but it's too soon to tell for that so I will update in a month or so.