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Tuesday, 21 May 2013

What do API Classifications for Automotive Gear Oils mean?

Understanding the API classifications for automotive gear oils.

Anyone that’s ever read their cars handbook or had a look at the fluids spec sheet will have seen that gear oils all have the prefix API: What do these API classifications for automotive gear oils mean?

The American Petroleum Institute (API) service designations are based on the type of service in which components will be used. The designations are utilized by manufacturers to select lubricants for particular gear types and operating conditions.

No attempt is made by the API classification system to
classify gear oils by physical properties or test performance. It also recognizes that some lubricants are suitable for a wide range of operating conditions and may be recommended for more than one service designation.

Although API designations may be very useful when making general recommendations, manufacturer recommendations should always be consulted to ensure that the lubricant being considered is approved by that manufacturer for the particular application.

The API Classifications for Automotive Gear Oils summarised.

API-GL-1 designates the type of service characteristics of automobile spiral bevel and worm gear axles as well as some manually operated transmissions operating under such mild conditions of low unit pressures and sliding velocities in which straight mineral oil can be used satisfactorily.

Oxidation and rust inhibitors, defoamers and pour-point depressants may be utilized to improve the characteristics of lubricants for this service. Frictional modifiers and extreme pressure (EP) agents are not used. This designation is recommended for use in some manual truck transmissions.

API-GL-2 refers to the type of service characteristics of automotive type worm gear axles operating beyond GL-1. It may contain anti-wear and very mild EP agents, and usually includes fatty additives for worm gears. This service designation is obsolete.

API-GL-3 describes the type of service characteristic of manual transmissions and spiral bevel axles operating under moderately severe conditions of speed and load beyond GL-2 but below GL-4. It may have mild EP agents but is not intended for hypoid gearing. Again this API classifications for automotive gear oils is obsolete.

API-GL-4 classifications for automotive gear oil relates to the type of service characteristics of gears, particularly hypoid gears operated under non-critical, moderate speed, shock load; high speed, low torque; and low speed, high torque conditions.

API-GL-5 designates the type of service characteristics of gears, particularly hypoid gears in passenger cars and other automotive equipment operated under high speed, shock load; high speed, low torque; and low speed, high torque conditions. This classification for automotive gear oils is still widely used for EP fluids.

API-GL-6 is associated with oils that reduce gear scuffing in older high-performance cars. This service designation is obsolete.

API-MT-1 describes a high EP oil intended for some non-synchronized manual truck and bus transmissions.

Mack and Volvo trucks (as well as others) have their own classifications for automotive gear oil that addresses some conditions beyond GL-5. These are Mack GO-J+ and Volvo 97310, although these numbers change every few years.

Using the API classifications for automotive gear oils to select the correct oil.


Now that you have an understanding of what the API classifications for automotive gear oil means, it’ll make the task of understanding why a specific classification is specified for your vehicle. Before purchasing, make sure the oil is specified/ compatible for your specific vehicle (By the manufacturer.)

At Habot Synthetic Lubricants we have quality synthetic gear oil that meet and exceed the requirements of the API classifications for automotive gear oils. Give us a call or send us an Email with your requirements

1 comments:

PTFE seals said...

PTFE seals are generally used in conjunction with rubber elastic material or metal spring, which provide the necessary contact pressure and preload with the sliding surface.