{"product_id":"red-line-mt-90-75w-90-gl-4-manual-transmission-lubricant-1-quart-x2-synchronizer-safe-smooth-shifting","title":"Red Line MT-90 75W-90 GL-4 Manual Transmission Lubricant — 1 Quart x2, synchronizer-safe smooth shifting","description":"\u003cp\u003e\u003cstrong\u003eRed Line MT-90 75W-90 GL-4 is a high-performance manual transmission and transaxle lubricant formulated to protect gears and synchronizers while delivering smooth, predictable shifts.\u003c\/strong\u003e\u003c\/p\u003e\n\n\u003cp\u003eThis MT-90 manual transmission lubricant from Red Line is engineered for gearboxes and transaxles that require GL-4 (and compatible GL-1\/GL-3) fluids. It uses a 75W-90 viscosity to provide reliable protection across a broad temperature range, avoid corrosive reactive sulfurs common in GL-5 formulations, and maintain excellent synchronizer friction characteristics so shifting stays crisp and low-notice. The product comes in convenient 1-quart bottles sold as a two-pack for easy service intervals or multi-vehicle maintenance.\u003c\/p\u003e\n\n\u003ch3\u003eWhat makes MT-90 suitable for manual transmissions and transaxles?\u003c\/h3\u003e\n\u003cp\u003eMT-90 is formulated specifically for the challenges of manual gear sets and synchronizers. It balances wear protection with a synchronizer-friendly friction profile, which prevents sticky or notchy shifts and helps extend synchro life. It is recommended where GL-1, GL-3, or GL-4 specifications are called for.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eGL-4 chemistry safe for brass and bronze synchros\u003c\/li\u003e\n  \u003cli\u003e75W-90 viscosity for stable film strength across temperatures\u003c\/li\u003e\n  \u003cli\u003eDesigned to reduce gear wear and extend component life\u003c\/li\u003e\n  \u003cli\u003eEliminates notchy shifting, improving drivability\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eHow does MT-90 help with shifting performance in cold or hot conditions?\u003c\/h3\u003e\n\u003cp\u003eThis formula maintains an appropriate coefficient of friction at low and high temperatures, providing predictable synchronizer engagement and quicker gear changes. Drivers notice smoother shifts immediately after fill, and the viscosity choice helps preserve protection during both cold starts and sustained highway runs.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003e75W rating improves cold-flow for easier cold-weather shifts\u003c\/li\u003e\n  \u003cli\u003e90 high-temperature behavior keeps oil film on gear faces\u003c\/li\u003e\n  \u003cli\u003eConsistent synchronizer performance reduces shift effort\u003c\/li\u003e\n  \u003cli\u003eStable formulation minimizes viscosity breakdown over time\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhich vehicles and applications are appropriate for this oil?\u003c\/h3\u003e\n\u003cp\u003eUse MT-90 in manual transmissions, transaxles, and differentials requiring GL-4 (or compatible GL-1\/GL-3) lubricant. It’s especially recommended where manufacturers advise against GL-5 due to reactive sulfur content that can harm brass synchros. Check your owner's manual for recommended gear oil viscosity ranges including 75W-90, 80W, or SAE 40 equivalents.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eManual gearboxes specifying GL-4 or special synchromesh fluids\u003c\/li\u003e\n  \u003cli\u003eVehicles with brass or bronze synchronizers sensitive to GL-5\u003c\/li\u003e\n  \u003cli\u003eApplications calling for 75W-90, 80W, or SAE 40 viscosity ranges\u003c\/li\u003e\n  \u003cli\u003eEnthusiast and performance cars where shift quality matters\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy choose Red Line MT-90 over generic gear oils?\u003c\/h3\u003e\n\u003cp\u003eRed Line has a long reputation for performance lubricants tailored to specific driveline needs. MT-90 is blended to protect gears and synchronizers without the sulfur additives that can attack yellow metals. The formula targets improved component life and a more refined shift feel compared with generic GL-5-heavy gear oils.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eNo reactive sulfurs that damage brass synchros\u003c\/li\u003e\n  \u003cli\u003eEngineered synchronizer friction for smoother shifts\u003c\/li\u003e\n  \u003cli\u003eTrusted brand with a history of specialty lubricants since 1979\u003c\/li\u003e\n  \u003cli\u003eSold in convenient 1-quart bottles, two-pack for service convenience\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eWho is this for: Red Line MT-90 75W-90 GL-4 MTL is ideal for DIY mechanics, performance-minded drivers, and workshop technicians who service manual transmissions, transaxles, and differentials that specify GL-4 or synchromesh fluids. It's particularly well suited for vehicles with brass or bronze synchronizers where GL-5 oils are not recommended and for anyone who wants improved shift quality and long-term gear protection.\u003c\/p\u003e\n\u003csection class=\"product-faq-snippet\"\u003e\u003ch3\u003eFAQ\u003c\/h3\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Is MT-90 safe for synchronizers made of brass?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: Yes. MT-90 is a GL-4 formulation that avoids reactive sulfurs found in GL-5, making it safe for brass and bronze synchronizers.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"faq-item\"\u003e\n\u003cp class=\"faq-q\"\u003eQ: Can I use Red Line MT-90 in place of SAE 40 motor oil?\u003c\/p\u003e\n\u003cp class=\"faq-a\"\u003eA: MT-90 matches gear oil viscosity needs (75W-90) and can be used where SAE 40 equivalents are specified for gearboxes, but check your manual before substituting oils.\u003c\/p\u003e\n\u003c\/div\u003e\u003c\/section\u003e","brand":"Red Line","offers":[{"title":"Default Title","offer_id":48083141787806,"sku":"B00NT5V8RW","price":63.19,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/2041\/9486\/files\/red-line-mt-90-front-label_a8faedce-5f1e-4115-935f-532ea8dea530.jpg?v=1785826360","url":"https:\/\/northtrailauto.ca\/products\/red-line-mt-90-75w-90-gl-4-manual-transmission-lubricant-1-quart-x2-synchronizer-safe-smooth-shifting","provider":"North Trail Auto","version":"1.0","type":"link"}