With the development of electric vehicles (EVs), the demand for electric transaxles is growing. As a critical component of EVs, the performance and lifespan of electric transaxles are closely tied to the quality of the lubricants used. Synthetic lubricants, known for their superior performance, have become the preferred choice for electric transaxles. Below is a detailed introduction to some of the best synthetic lubricants for electric transaxles:
Performance Requirements for Electric Transaxle Lubricants
Electric transaxles operate under unique conditions, such as high torque at low speeds, exposure to electrical fields, high voltage environments, and localized heat loads. Therefore, lubricants must meet specific performance requirements:
Low electrical conductivity: To prevent current leakage and ensure safety in electrical systems, the lubricant should have low electrical conductivity to avoid affecting the normal operation of electrical components.
Low viscosity: Lower viscosity reduces fluid resistance, enhances energy efficiency, and ensures smooth lubrication of gears and bearings. This is particularly important for extending the driving range of EVs. At the same time, the lubricant should have a high viscosity index to maintain stable viscosity across a wide temperature range.
Low traction: Minimizing the shear resistance between fluids helps reduce energy loss and improve the efficiency of the electric transaxle.
Excellent wear protection: Electric transaxles operate under high loads and require lubricants with effective anti-wear and extreme pressure additives to protect gears, bearings, and other components from wear, thereby extending their lifespan.
Good thermal conductivity: Effective heat dissipation is crucial for maintaining optimal operating temperatures of electric transaxles. Lubricants with strong thermal conductivity can promptly dissipate heat generated during operation, preventing overheating and thermal degradation of the lubricant.
Chemical stability: Electric transaxles generate significant heat during operation, making the lubricant prone to oxidation and thermal breakdown. Thus, the lubricant must possess high oxidative and thermal stability to resist degradation, prolong service life, and maintain long-term performance.
Common Synthetic Base Oils for Electric Transaxle Lubricants
PAO (Polyalphaolefin): A widely used synthetic base oil, PAO offers excellent viscosity-temperature properties, low pour point, high viscosity index, good oxidative stability, and chemical resistance. It provides superior lubrication performance across a broad temperature range, effectively reducing friction and wear in electric transaxles. However, PAO has poor solubility for polar additives and may exhibit slight shrinkage of seals.
Ester base oils: Ester base oils exhibit strong polarity, enabling excellent solubility for additives. They also provide good lubricity, anti-wear properties, and high oxidative stability. Ester base oils can enhance the performance of lubricants by improving wear protection and oxidative resistance. However, certain ester base oils may have compatibility issues with some seal materials.
Polyglycol base oils: Polyglycol base oils feature low viscosity, high viscosity index, excellent low-temperature fluidity, and strong hygroscopicity. They can effectively absorb moisture, preventing water from interfering with the lubrication process. Additionally, they offer good lubricity and anti-wear properties, making them suitable for the lubrication needs of electric transaxles. However, polyglycol base oils may cause swelling of seals and are toxic, requiring careful handling during use.
Recommended Synthetic Lubricants for Electric Transaxles
AMSOIL Synthetic Manual Transmission and Transaxle Gear Lube 75W-90 API GL-4 (MTG):
Features: Formulated with premium synthetic base oils and advanced high-performance additives, it provides maximum protection for demanding manual transmission and transaxle applications. It resists thinning caused by mechanical shear, maintains viscosity and film strength, and delivers long-lasting wear protection. It performs well in extreme hot and cold temperatures, surpassing conventional mineral oils. It protects against rust, keeps seals supple for extended life, and is compatible with brass synchronizers, ensuring smooth shifting.
Applications: Suitable for synchronized manual transmissions and transaxles requiring 75W-85, 75W-90, or 80W-90 viscosities and meeting API GL-4 and MT-1 performance specifications. It is ideal for NV-4500 transmissions, muscle car transmissions, and front-wheel-drive transaxles.
ENEOS EV/Hybrid e-Axle Fluid MODEL TE:
Features: Developed using ENEOS’s advanced base oil technology, this lubricant outperforms traditional ATF or gear oil in thermal and oxidative resistance. Its low viscosity ensures better flow at low temperatures, improving energy efficiency. Its high-viscosity-index base oil exhibits minimal viscosity change with temperature fluctuations, reducing resistance in the e-axle and enhancing energy efficiency. The base oil’s molecular structure enables smooth lubrication under high-pressure conditions, significantly boosting EV energy efficiency.
Applications: Compatible with e-axles requiring “Toyota Genuine e-Transaxle Fluid TE.”
Gulf Driveline Fluid:
Features: Specifically designed for wet/dry, single- and multi-speed transmissions in rear axles and transaxles of EVs, particularly where axle fluid comes into direct contact with electrical components. It meets the unique lubrication requirements of EV drivetrains, offering effective protection for gears and bearings in electric transaxles.
Applications: Suitable for various EV models, providing reliable lubrication and protection for electric transaxles.
Cargill Priolube” EF Low Viscosity Group V Ester Base Oils:
Features: Enables the formulation of lubricants with a low traction coefficient. It is compatible with Group III, IV, and ester base oils and is suitable for high-efficiency fluids in transmissions, gearboxes, and motors. For example, Priolube” EF 3446 has a kinematic viscosity of 6.1 cSt at 40°C, a pour point of -40°C, and a NOACK volatility of 9.6% at 200°C. It is readily biodegradable, aligning with environmental sustainability trends.
Applications: Can be used to formulate lubricants for electric transaxles, improving the efficiency and performance of EV drivetrains.
Lubrizol Evogen Driveline Fluids:
Features: Engineered to address the unique challenges of e-axles. These fluids are thinner than traditional axle lubricants, offering greater efficiency and improved heat transfer properties. They strike a balance between anti-wear and extreme pressure chemistry to protect hardware. They also possess precise electrical and conductive properties to ensure hardware durability and personal safety.
Applications: Suitable for e-axles in EVs, providing effective lubrication and protection for gears and bearings in electric transaxles.
Factors Influencing the Selection of Synthetic Lubricants for Electric Transaxles
Manufacturer recommendations: Vehicle manufacturers design electric transaxles based on specific technical requirements and typically recommend lubricants in user manuals or service guides. Following these recommendations ensures optimal performance and lifespan of the electric transaxle.
Operating temperature range: If the electric transaxle operates in extreme temperatures, synthetic lubricants with a wider viscosity range (e.g., SAE 75W-90 or SAE 80W-90) are preferable. These lubricants maintain good fluidity at low temperatures and provide sufficient viscosity and protection at high temperatures.
Driving conditions: For harsh driving conditions such as off-road driving or frequent heavy traffic, lubricants with higher performance characteristics, stronger anti-wear properties, and better oxidative stability should be chosen to protect the electric transaxle from damage.
Age and condition of the electric transaxle: Older electric transaxles with greater wear may benefit from higher viscosity lubricants to enhance film strength and protect components. Newer electric transaxles can use lubricants with lower viscosity to improve efficiency.
Benefits of Using Synthetic Lubricants for Electric Transaxles
Enhanced efficiency: The low viscosity and high viscosity index of synthetic lubricants reduce internal friction and resistance in electric transaxles, improving transmission efficiency and extending the driving range of EVs.
Prolonged lifespan: Synthetic lubricants’ superior wear protection, oxidative stability, and thermal stability prevent premature wear and damage to gears, bearings, and other components in electric transaxles, extending their service life.Improved reliability: Synthetic lubricants’ excellent low-temperature fluidity and high-temperature stability ensure reliable lubrication for electric transaxles across a wide temperature range, reducing the risk of lubrication failures and enhancing vehicle reliability.
Enhanced safety: The low electrical conductivity of synthetic lubricants minimizes the risk of electrical issues caused by current leakage, ensuring the safe operation of EVs.
In summary, selecting the appropriate synthetic lubricant for electric transaxles is critical to improving their performance, lifespan, and reliability. When choosing a lubricant, factors such as the manufacturer’s recommendations, operating conditions, and the specific requirements of the electric transaxle should be considered comprehensively. The synthetic lubricants mentioned above are excellent options for electric transaxles, offering superior performance and protection. Users can choose the most suitable product based on their needs and budget.
Post time: May-21-2025