What Are the Models of Manual Transmission Fluid?
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Manual transmission fluid, commonly referred to as gear oil, comes in six models: GL-1, GL-2, GL-3, GL-4, GL-5, and GL-6. Here is some relevant information about manual transmission fluid: 1. Model Introduction: Manual transmission fluid, also known as gear oil, includes five grades: GL-1 to GL-5. GL-1 to GL-3 have higher performance requirements and are used for most lubrication purposes. GL-4 is used for lubrication under conditions of high speed with low torque or low speed with high torque. GL-5 offers the best performance and is used for transmission lubrication under severe operating conditions with high impact loads. 2. Selection of Transmission Fluid: The selection of automotive gear oil includes the following: general-purpose gear oil (GL-3), suitable for spiral bevel gear differentials, transmissions, and steering gears under mild operating conditions, such as the rear axle and transmission of the Jiefang CA1091 vehicle. The viscosity grades (SAE) correspond to 90, 80W/90, and 85W/90, suitable for year-round use in regions with temperatures ranging from -10°C to 20°C.
Manual transmission fluid models are mainly divided into three categories: First, performance grade models like GL-4 and GL-5. GL-4 is the most commonly used and suitable for most manual transmission vehicles; GL-5 is often used for high-performance or heavy-duty vehicles, but be aware that GL-5 contains corrosive additives, and using the wrong type can damage synchronizers. Second, viscosity models, such as 75W-90, which is the most common and ensures smooth cold starts in winter; 80W-90 is better suited for tropical regions with superior high-temperature resistance. Third, special OEM models, like Volkswagen G50 certification or Toyota WS, which are vehicle-specific oils and are clearly marked in the manual. When selecting oil, always refer to the manual requirements first, and never mix different models arbitrarily, as this can cause transmission noise or even gear grinding.
We seasoned drivers pay most attention to viscosity grades when changing manual transmission oil. Fully synthetic 75W-90 oil remains smooth even at -30°C in winter, making it particularly suitable for northern regions. For southern areas with year-round high temperatures, 80W-90 offers better durability. I remember once helping a friend fix his car and discovering he'd mistakenly used GL-5 differential oil - it caused gearshift hesitation and smoke until we switched back to GL-4. Nowadays some new cars require special low-viscosity oils like 75W-80 for better fuel economy, but older vehicles might experience seal leaks with these. Remember three key points: choose viscosity based on local climate, verify GL rating in the manual, and always change oil after 50,000 kilometers.
Manual transmission oils are categorized into mineral, semi-synthetic, and full synthetic. Mineral oils like 80W-90 are the cheapest but require replacement every 20,000 km. Semi-synthetic 75W-85 offers better anti-wear performance, while full synthetic 75W-90 has the longest service life. Last time I used Red Line's full synthetic oil, it remained clear even after 80,000 km. Note: Do not mix GL-4 and GL-5 oils, as GL-5's higher sulfur content can corrode brass synchronizers. Enthusiasts modifying their cars can try ester-based full synthetic oils for no-slip performance during aggressive track shifting. Northern drivers should prioritize winter-grade oils with 'W' ratings to prevent transmission freeze-ups during cold starts.
