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What’s the difference?
API GL-5: The building block to Change API GL-5: An update, not a new standard Beyond API GL-5 Ask the right questions
Just as the operating demands on vehicles vary widely, so too do the demands on the gear lubricants that must keep axles and manual transmissions functioning flawlessly and reliably.
Variations in speed, torque and other operating conditions all present different challenges under real-world conditions. The more exacting the demand for performance, the more essential it is that lubricants rise to the challenge.
The continuous development and clarification of industry specifications – supplemented by original equipment manufacturers’ own standards for their unique requirements – reflects the distinct performance requirements of today’s vehicles and their end users.
Clearly defined industry performance specifications are intended to enable OEMs, end-users, oil marketers and lubricant additive manufacturers anywhere in the world to speak the same language when it comes to lubricants. The standards are your assurance that gear oils are up to the challenge, so it’s important to understand what they mean.
The performance requirements for automotive gear lubricants depend on their intended use.
* API Categories GL-1, GL-2, GL-3 and GL-6 were declared inactive by SAE Technical Committee 3 in 1995, even though oils may be marketed with these designations. Similarly, ASTM does not plan to maintain the performance tests associated with these categories, as in a number of cases these tests can no longer be run because parts or test installations are not available.
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More and more, end-users worldwide are finding that the performance defined by API GL-5 is the practical minimum to deliver acceptable performance and equipment dependability. As a result, API GL-5 may be regarded as the industry’s fundamental building block in growing numbers of the world’s regions. The tests indicated on the following table provide end-users the assurance of a basic level of gear oil performance.
Confusion and ambiguity that once surrounded the API GL-5 standard should rapidly be alleviated, thanks to a forthcoming rewrite – or update – of the standard.
Previously, some users found it difficult to access the test equipment and ASTM STP 512A, which was the book that contained the API GL-5 test information, and was primarily a compilation of test procedures. The update is in the form of an ASTM Standard, easily accessible to anyone who needs it.
In addition, there was no process in place to periodically review and update the standard. As a result, references to certain test methods became outdated and there was potential for confusion regarding what constitutes an acceptable result. The update includes current test procedures and reference oils, and designation as an ASTM Standard requires review and revalidation every five years.
The rewrite is the result of more than one year of work by a technical committee of ASTM International, one of the world’s largest voluntary standards development organizations. The committee included representatives of oil marketers, dependent and independent testing facilities, the military and additive manufacturers, including Lubrizol.
Increasingly, original equipment manufacturers and end-users are seeking lubricant performance qualities that exceed those of API GL-5. The SAE J2360 is an example of a standard that defines a level of performance beyond API GL-5.
By far the premier standard in common use today, SAE J2360 is a global quality standard specified by many North American OEMs and by growing numbers elsewhere in the world. The rigorous approval requirements, including controlled field testing and independent committee review, ensure that products approved under the SAE J2360 Standard meet the very highest demands of axles and non-synchronised manual transmissions.
SAE J2360 will have a significant impact in parts of the world where the MIL-PRF-2105E specification has not been available. The lack of a global performance standard has resulted in various degrees of quality throughout the world. The lack of uniform quality is regarded by many as the cause for warranty issues for OEMs and equipment problems for end-users. The transition to SAE J2360 should result in an overall increase in performance level for automotive gear lubricants globally.
In 1986, the SAE outlined the trucking industry's need for a gear lubricant category which would provide performance characteristics essential to ensure optimum service life for heavy-duty non-synchronised manual transmissions. It was determined the class of oils used in manual transmissions was not always in compliance with the builder's primary recommendations. API Category MT-1 was developed to satisfy OEM objectives for optimum transmission performance and service life. This was achieved by combining in a single lubricant the cleanliness and oil seal life typical of engine oils with the load characteristics of gear oil.
