Now Is the Time for Improved Axle Protection

In Latin America, estimates indicate that the majority of commercial vehicles on the road today are using gear oils that lack the capability to protect components from industry realities, like problems associated with high temperatures. While API GL-5 is more than 50 years old, over 50% of the automotive gear oils currently used in Brazil are API GL-4 or GL-5. In Mexico, 50% of the automotive gear oils currently in use are API GL-1. In these two markets, which represent around 65% of the Latin American automotive gear oil market, only around 8%-9% of commercial trucks are older than 26 years. What’s most concerning about the use of API GL-5 gear oils is that the average age of commercial vehicles in Brazil and Mexico is around 12 years. This discrepancy between the age of the fleet and the automotive gear oils in use reveals a glaring performance gap. In short, the needs of many commercial vehicle axles in this region are not being met. This fact has implications for the current demands of the market. 

Pushing the Limits of Current Fluids 

Latin American markets are demanding gear oils that perform better than the products that currently dominate the market. A close look illustrates why: 

• Higher overall loads from increased torque and overloading of vehicles demand gear oils with robust additive technology to protect critical parts. 
• Market demands for lower total cost of ownership requires innovation and keeping lubricant costs competitive, especially for out-of-warranty or older vehicles. 
• Evolving vehicle performance requires lubricants that deliver above API GL-4 and API GL-5. 
• Components facing increasing operating temperatures depend on lubricants that have higher levels of thermal stability. 
• The drive for fuel economy and reduced emissions demands a holistic solution that includes gear oils. 

Better performing gear oils are needed to match the harsher conditions characteristic of the current market. The current market demands better operational efficiency, improved uptime, and reductions in maintenance and downtime. All of these can lead to cost savings that translate to bigger profits. Better gear oils are the way for fleet owners to meet these goals. 

The challenge of balancing efficiency with the unwanted side effects of steps taken to improve efficiency cannot be overstated. Consider how the pursuit of fuel efficiency has added to the concerns around the ability of current gear oils to function properly. To start, the push for better fuel efficiency has led to several changes to the design of commercial vehicles. Many of these changes contribute to higher temperatures, which is a challenge to lubricants:  

• Improved aerodynamics lead to better fuel efficiency, but not without a cost. Better aerodynamics mean reducing the cooling effects of airflow around the axle, pushing temperatures higher. 
• Increased power density means more power, obviously, but often through smaller pieces of equipment. Increasing power density is often a result of lightweighting, a strategy based on the idea that less weight means better fuel economy, less material costs and less power required to move its components. But it also results in higher temperatures because a component is being exposed to more energy and heat. 
• Smaller components affect the lubricant volume. A smaller amount of fluid is tasked with cooling the components, even as there is less lubricant chemistry involved. 
• Anti-noise shielding contains noise pollution but also effectively insulates the axle, leading to increasing temperatures. 

The challenge of addressing high temperatures falls on the lubricant, which has more adversity to face. High temperatures can lead to quicker oxidation and more oxidatively formed deposits. The lubricant can also degrade faster as it breaks down and its additives are depleted. This has acute consequences for the lubricant as it counteracts wear and contamination. 

The market realities and operational policies can also affect commercial vehicles via harsh duty cycles. Like changes to the vehicles themselves, the way the vehicles are driven can also challenge components and the lubricants tasked with protecting them. With hills, dust and inclement weather in many Latin American markets, roads can be inhospitable for vehicle components. When commercial vehicles are continuously run fully loaded and sometimes 24/7 with teams of drivers, the conditions are considerably worse. Harsh duty cycles only increase the chances of lubricant-related failures. 

Given changing trends around components and habits, the traditional axle lubricant meeting API GL-5 is not prepared to meet new performance criteria. This is not surprising given the fact that the API GL-5 standard does not address thermal stability and oil seal compatibility, nor does it require a field test and independent review.  

The Specification Landscape 

Some estimates indicate that more than 50% of the gear oils commercialized in Latin America do not meet the performance needs of the current vehicle parc. Some of these gear oils are API GL-5 oils, the performance of which are validated via five tests: 

• ASTM D130 helps determine the corrosiveness of the gear oil by submerging a polished copper strip in the fluid for a period under controlled temperature. 
• ASTM D5704 (L-60) simulates a high-temperature environment that can break down the lubricant and its capabilities. It evaluates the ability of a lubricant to resist deterioration associated with high temperatures within final drive axles. 
• ASTM D7452 (L-42) simulates the high speed and shock loading operational environment within the final drive axles. This test evaluates the ability of a lubricant to resist surface damage like scoring. 
• ASTM D6121 (L-37) simulates the extreme load and high-pressure operational environment inside the hypoid drive axle of a large truck. This test evaluates the ability of a lubricant to carry loads and resist wear and extreme pressure due to low-speed, high-torque operation. 
• ASTM D7038 (L-33-1) simulates an operational environment in which moisture has entered a drive axle assembly. This test evaluates the ability of a lubricant to resist corrosion due to water contamination and high temperatures. 

The performance of J2360 oils is validated by the GL-5 tests above plus three additional tests: 

• ASTM D5662 (Oil Seal Compatibility) helps determine the compatibility of gear oils with the oil seal elastomers. The test helps predict if a gear oil might cause oil seal failure via hardening, elongation loss and swelling. 
• ASTM D5704 (L-60-1) helps determine the susceptibility of a gear oil to thickening, insolubles formation and deposit formation under high-temperature conditions conducive to oxidation. 
• ASTM D7503 (Storage Stability and Compatibility) helps ensure the integrity of the oil during storage and its compatibility with other oils meeting SAE J2360. 

While all the tests for API GL-5 and J2360 are simulations of real-world conditions on stationary test rigs, the strongest performance validation of the J2360 specification is a field trial on real vehicles in real world conditions, followed by an independent review. During the field trial, axle oils for light-duty vehicles must protect equipment for 100,000 miles without a change of oil. Axle oils for heavy-duty vehicles are required to protect for 200,000 miles without an oil change. After the SAE J2360 tests are complete, an independent group of industry experts reviews the test data and visually inspects test parts. Axle oils meeting SAE J2360 are included in the Qualified Products List (QPL) on the website of the Performance Review Institute (https:p-r-i.org/). The manufacturer of each qualified oil pledges to not change the approved formulation, ensuring the axle oil in any vehicle is the same formulation that endured the rigorous SAE J2360 approval process.  

The Need for a Thermostable Fluid 

Taken together, the requirements for J2360 certification can take up to four years and cost over $500,000 USD. This is a significant investment of time and money for the peace of mind of proven performance. Clearly, the additional stationary testing, field testing and independent review elevates SAE J2360 gear oils beyond what is considered the norm in Latin American markets.   

Besides other benefits and robustness, automotive gear oils certified to SAE J2360 have the thermostability that API GL-5 oils lack and thus offer superior protection. Given all the changes to new vehicles, a modern Latin American fleet under warranty will require SAE J2360 fluids as the minimum level of performance.  

However, SAE J2360 may not be necessary for some out-of-warranty vehicles in the Latin American market currently being served by API GL-5 oils. Due to market demands, these vehicles require a better performance gear oil than API GL-5 and may be better served by an appropriate thermostable fluid with better performance under higher temperature and higher load conditions. With such a large unmet need, a viable thermostable fluid suited to the majority of trucks on the road is a compelling opportunity for oil marketers in the region. With the right technology, a thermostable gear oil can have an enormous impact for commercial vehicles in the region and contribute as well to the overall health of the environment.  

Edson Fonseca is driveline product manager, Latin America, for the Lubrizol Corporation.