Differences Between Gear Oil Grades 150, 220, and 320

[LaMorgan]

Mainly used for lubrication between the transmission and rear axle, gear oil differs from engine oil. Its primary functions include lubricating gears and bearings, preventing wear and rust, and assisting in heat dissipation for gears. The specific differences are as follows: 1. Grade 220 is slightly thinner than grade 320: Grade 320 is thicker than grade 220, with slightly different specific parameter indicators. The kinematic viscosity (100°C)/(mm²/s) for grade 220 ranges from 198 to <242, while for grade 320, it ranges from 288 to <352. Other parameters are basically the same. It is essential to select the appropriate grade based on the equipment's usage instructions, as they cannot be used interchangeably. 2. Adhesion: Both grade 220 and grade 320 gear oils refer to medium-load gear oils (CKC), representing medium extreme-pressure gear oils used in machinery equipment such as transmissions, reducers, turbines, and gearboxes. The characteristics of this series of lubricants include excellent load-carrying capacity and anti-scuffing properties, outstanding thermal and oxidation stability, good adhesion, and they are free from solvents, asphalt, heavy metals, and chlorine, meeting environmental protection requirements.

[LeBraxton]

I've been driving for over a decade and have used various gear oils. The main differences between SAE 150, 220, and 320 lie in viscosity and temperature adaptability. SAE 150 is thinner, suitable for low-temperature environments like winter or cold regions, allowing quick gear lubrication and reducing startup wear. SAE 220 has medium viscosity with strong versatility, suitable for all seasons, especially performing well in moderate climates. SAE 320 has the highest viscosity, ideal for high-temperature environments or heavy-duty use, such as in consistently hot areas or fully-loaded trucks, providing better protection against overheating and wear. Beyond seasonal factors, vehicle type matters too - passenger cars typically need SAE 150 or 220, while heavy trucks or off-road vehicles may require SAE 320. Using oil that's too thin or thick can lead to insufficient lubrication and increased fuel consumption. Regular oil changes are crucial, and blindly choosing higher-grade oil isn't advisable - I've seen cases where wrong oil usage accelerated transmission aging. Always follow the manual's recommended viscosity to properly protect your vehicle and extend its lifespan.

[VonRowan]

I usually enjoy tinkering with car parts. Gear oils labeled 150, 220, and 320 represent different viscosity grades. The 150-grade oil flows quickly, provides excellent low-temperature startup performance, and ensures smooth gear rotation in cold weather. The 220-grade is suitable for spring and autumn seasons, with moderate fluidity, making it ideal for most daily driving scenarios. The 320-grade is very thick and remains stable even under high temperatures, offering protection for heavy-duty equipment like construction machinery or truck transmission systems. The difference lies in the thickness of the oil film—thinner oil lubricates easily but offers weaker protection, while thicker oil is more wear-resistant but increases friction. When selecting, refer to the viscosity range recommended in your vehicle's manual and consider the ambient temperature. Using a lower-grade oil in hot weather may cause oil burning, while a higher-grade oil in cold weather can make starting difficult. From personal experience, mixing oils is not advisable, as performance degrades when oil temperatures get too high. Regularly check the oil color—if it turns black, it’s time for a change. Choosing the right oil can reduce gear wear and extend transmission life.