What is the difference between gear oil 220 and 320?
4 Answers
Here is the relevant information about the differences between 220 and 320: 1. The 220 grade is thinner than the 320 grade, while the 320 grade is thicker than the 220 grade. The specific parameter indicators are slightly different. The kinematic viscosity (100°C)/(mm2/s) for the 220 grade is 198~<242, and for the 320 grade, it is 288~<352. Other parameters are basically the same. It is essential to select the appropriate grade according to the equipment's instructions, and they cannot be used interchangeably. 2. The 220 and 320 gear oils refer to medium-load gear oil CKC, representing medium extreme pressure gear oil, generally used in machine equipment such as gearboxes, reducers, turbines, and gear cases. The characteristics of this series of lubricants include good load-carrying capacity and anti-scuffing properties; excellent thermal stability and oxidation stability; good adhesion; and they are free of solvents, asphalt, heavy metals, and chlorine, meeting environmental requirements.
In gear oil model numbers, 220 and 320 represent SAE viscosity grades, indicating different thickness levels. 220 is thinner, flowing quickly like water, making it suitable for regular sedans or small-displacement vehicles because it offers less resistance at high gear speeds, improving fuel efficiency and easier starts. 320 is thicker, providing stronger protection, ideal for heavy-duty vehicles like pickup trucks or SUVs, preventing wear under heavy loads or high temperatures. Always refer to the owner's manual for recommendations—using the wrong viscosity may cause gearshift hesitation or increased noise. I remember once when a friend used higher-viscosity oil in his car, it struggled to start in winter and consumed more fuel. Additionally, synthetic oil is more stable than mineral oil, adapting to varying temperatures, but viscosity matching remains key. 220 is typically popular in colder regions, while 320 is more common in tropical areas—choosing the right oil extends transmission lifespan.
Living in a southern city, I pay special attention to gear oil when driving. The 220 viscosity is low with good fluidity, forming a thin oil film that dissipates heat quickly under summer high temperatures, making it suitable for small-displacement urban commuting vehicles. The 320 viscosity is higher with stronger stickiness, providing better gear protection during hot weather or mountain driving. If used on lightweight vehicles, you might experience less smooth gear shifting or even increased fuel consumption. The key is to choose according to the manufacturer's specifications - generally, 220 is sufficient for passenger cars, while 320 is needed for heavy-duty vehicles. My experience is to check oil levels in both winter and summer, as oil quality changes can affect the entire transmission system. Also, pay attention to brand differences - some premium oils offer better stability, but the core factor remains the viscosity number. Prolonged incorrect selection will accelerate component wear.
For long-distance transportation, my experience is that gear oil makes a big difference. SAE 220 is thinner, saving some fuel but offering weaker protection; SAE 320 is thicker and more durable, suitable for heavy loads to prevent wear. The two have different SAE grades—the higher the number, the stronger the viscosity. I've seen many owners carelessly switch oils, resulting in light vehicles using SAE 320 having slower starts and louder noise, while heavy vehicles using SAE 220 tend to overheat. It's best to choose viscosity according to the manufacturer's guidelines, balancing driving conditions and habits. In the long run, regular fluid checks are essential.
