Gear oil mainly refers to the lubricating oil used in transmissions and rear axles. It differs from engine oil in terms of usage conditions, composition, and performance. Gear oil plays a crucial role in lubricating gears and bearings, preventing wear and corrosion, and assisting in gear heat dissipation. There are two main types of gear oil: automotive gear oil and industrial gear oil. The former is used to lubricate various manual transmissions and gear-driven axles in automobiles, while the latter is used in lubricating gear systems in various industries such as metallurgy, coal mining, cement production, and chemical engineering.
Automotive gear oil
Automotive gear oil is used in gear transmission systems such as power steering, transmissions, and drive axles in vehicles. Due to the high surface pressure during gear transmission, gear oil plays a crucial role in lubricating gears, preventing wear, cooling, heat dissipation, corrosion and rust prevention, cleaning, as well as reducing surface impact and noise on the gears.
American Petroleum Institute (API) vehicle gear oil performance classification
| Use performance ratings | GL-1 | GL-2 | GL-3 | GL-4 | GL-5 |
| Lubricating oil type | Straight run or residual oil | Oil-containing agents, greases, straight-run or residual oil | Mixtures of straight-run or residual oil containing compounds such as sulfur, phosphorus, chlorine or extreme pressure agents such as zinc compounds | ||
| Scope of application | Low load and low speed spur gears, worm gears, bevel gears and manual transmissions, etc. | Worm gears and other gears with slightly higher speed, higher load and slightly harsh conditions (hypoid gears cannot be used) | GL-1 or GL-2 medium-load and medium-speed spur gears and manual transmissions cannot be used (hypoid gears are not applicable) | High speed low torque, low speed high torque hypoid gears and other gears working under very harsh conditions | For hypoid gears that are more demanding than GL-4 and can withstand low-speed high-torque, high-speed low-torque, high-speed, and impact loads. |
| Application area | Cannot meet automobile gear requirements and cannot be used in automobiles | It cannot meet the requirements of automobile gears and cannot be used in automobiles except under special circumstances. | Transmission, steering gears and differential gears with mild conditions | Differential gears, transmission gears and steering gears | Differential gears and rear axle gears with particularly harsh working conditions |
| Contains extreme pressure dose % | 2～4 | 3～6 | 6～10 |
Industrial gear oil
Industrial gear oil classification
| Grading | Current name | Composition, characteristics and instructions for use |
| L-CKB Anti-oxidation and anti-rust type | General industrial gear oil | It is formulated from refined mineral oil with anti-oxidation and anti-rust additives. It has strict anti-oxidation, anti-rust, anti-foam and anti-emulsification performance requirements and is suitable for general light-load gear lubrication. |
| L-CKC Extreme pressure type | Medium duty industrial gear oil | It is formulated from refined mineral oil with antioxidant, anti-rust, and extreme pressure anti-wear agents. It has better anti-wear properties than CKB and is suitable for medium-load gear lubrication. |
| L-CKD Extreme pressure type | Heavy Duty Industrial Gear Oil | It is formulated from refined mineral oil with anti-oxidation, anti-rust and extreme pressure anti-wear agents. It has better anti-wear and thermal oxidation stability than CKC, and is suitable for lubrication of heavy-duty gears operating at high temperatures. |
| L-CKE Turbine shaft | Worm gear oil | It is made of refined mineral oil or synthetic hydrocarbons and oily agents. It has good lubricating properties and anti-oxidation and anti-rust properties. It is suitable for worm gear lubrication. |
| L-CKT Synthetic hydrocarbon extreme pressure type | low temperature medium load Industrial gear oil | It uses synthetic hydrocarbons as base oil and adds additives similar to CKC. In addition to the characteristics of CKC, it has better low-temperature and high-temperature performance. It is suitable for the lubrication of medium-load gears in high and low-temperature environments. |
| L-CKS | Synthetic hydrocarbon gear oil | Using synthetic oil or semi-synthetic oil as the base oil and adding various corresponding additives, it is suitable for gear transmission lubrication at low temperature, high temperature or large temperature changes, flame resistance, heat resistance, chemical resistance and other special occasions. |
Six Key Performance Characteristics of Gear Oil
Gear oil is generally required to possess the following six basic performance characteristics:
- Appropriate viscosity and excellent viscosity-temperature behavior
- Adequate extreme pressure and anti-wear properties
- Good emulsion resistance
- Excellent oxidation stability and thermal stability
- Good foam resistance
- Effective rust and corrosion prevention
Choosing a suitable gear oil is essential to provide optimal protection for gears and extend the lifespan of machinery.
Thank you for reading this article, and we look forward to serving you with our exceptional gear solutions.
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