No one would deny the value of improving the durability and economical operation of commercial vehicles, and one crucial contributing factor is to use the highest quality driveline lubricants. An appropriate, high quality lubricant offers better protection to gears, seals and bearings, and improves efficiency to reduce fuel consumption and CO2 emission.
For axle lubricants, one of the traditional standards used to guide buyers in their choice has been API GL-5. The increasing demands on axle components have revealed performance shortcomings in the API GL-5 standard of performance. As a result, the lubricant industry is advocating for global adoption of the more comprehensive and up-to-date standard, SAE J2360.
The evolution of equipment and its increased sophistication has emphasized the shortcomings of API GL-5 for some time. More effective vehicle aerodynamics raising driveline operating temperatures through lack of cooling and the increased power of engines are both examples of why improvements in equipment design demand improved lubricants and a better standard for judging their effectiveness.
Today, priorities in the field of axle lubrication are improved surface protection and reduced fatigue, high thermal durability, thermal and oxidative stability and seal compatibility, all of which lead to a reduction in warranty claims.
A lubricant conforming to API GL-5 may not necessarily meet these criteria. For example, there is no test for oil seal compatibility included in the API GL-5 standard. Specifically, API GL-5 does not address shear stability, thermal stability, damage to oil seals through build-up of deposits. Perhaps most important, field testing is not even a requirement for meeting API GL-5.
To address these shortcomings, OEMs have formulated their own standards to ensure proper protection of equipment and safeguard against unnecessary warranty claims. Examples of these OEMs are Mercedes-Benz and MAN in Europe, and Dana and Meritor in North America. These OEMs specify lubricant technology to ensure that the lubricants used in their equipment provide improvements in thermal durability, cleanliness and seal compatibility not offered by API Category GL-5-quality lubricants.
The lubricant industry has replicated this approach for non OEM-branded lubricants through the introduction of the SAE J2360 Standard.
SAE J2360, which has its roots in military lubricant specifications dating back to the 1940s, emerged in the late 1990s and was updated in 2012 to ensure that it kept pace with the needs of the marketplace. This specification includes a comprehensive set of test requirements that address the shortcomings of API Category GL-5 and ensure that lubricants meeting this specification will provide the performance required by today’s modern equipment.
One of these tests is the ASTM D5704 test, commonly referred to as the L-60-1 test. This test ensures that the lubricant does not form sludge and/or hard and potentially abrasive deposits on shafts, gears and oil seals, any of which could result in oil seal leaks. If these leaks occur, lubricant may come in contact with critical components or leak into the environment.
Another important performance test which separates the SAE J2360 Standard from API Category GL-5 is the ASTM D5662 oil seal compatibility test. The purpose of this test is to identify lubricants which cause oil seals to harden, crack, and deteriorate due to chemical interaction between the lubricant and the seal. If the lubricant is not optimized to be compatible with the oil seals, they will leak, the oil level in the equipment will decrease, and equipment failure will follow.
A third test which separates the SAE J2360 Standard from API Category GL-5 is the ASTM D7603 Storage Stability and Compatibility Test, sometimes referred to as the SS&C test. Demonstrating acceptable performance in this test ensures that the lubricant will maintain its integrity during periods of prolonged storage, and that the lubricant will be compatible with other SAE J2360-approved lubricants which may be added to it, or to which it may be added, if it becomes necessary to top up equipment in the field.
There are two additional characteristics of SAE J2360-approved lubricants which separate them from API Category GL-5-quality lubricants. The first of these is that all lubricants which have gone through the SAE J2360 approval process have been shown to provide acceptable performance in controlled field tests in both light-duty and heavy-duty equipment. The light-duty portion of this test requires that the lubricant protect the equipment from life-limiting distress for 100,000 miles of service with no oil change, while the heavy-duty portion of this test requires that the lubricant protect the equipment from life-limiting distress for 200,000 miles of service with no oil change.
Once all tests have been completed, all of the data is reviewed by an independent panel of industry experts to ensure that the lubricant has met all of the demanding chemical, physical, and performance requirements of the SAE J2360 Standard. It is this combination of the additional stationary testing, field testing and verification of test data that clearly separates SAE J2360-quality lubricants from those which meet only the requirements of API Category GL-5.
So how do quality-conscious end-users identify and find lubricants which meet the demanding requirements of the SAE J2360 Standard? The answer is quite simple. All lubricants that have been shown to meet these requirements are included in a Qualified Products List (QPL), which can be found on the Performance Review Institute’s (PRI) website. This list provides the name of the manufacturer, the brand name of the product, and the unique qualification number which has been assigned to that lubricant. Additionally, each lubricant manufacturer who has requested that their lubricant be included on this list has certified that they will not change the formulation of the approved lubricant in any way. This is the end-user’s assurance that the lubricant being purchased is the very same as the lubricant which has undergone the rigorous process of obtaining an approval under the SAE J2360 Standard.
For more information, please contact your Lubrizol representative.