Comparison of Extended Service Lubricants for Heavy-Duty Transmissions and Axles

Over the past several years, economic pressures have driven fleets to substantially increase their maintenance intervals. To meet this challenge, both the Original Equipment Manufacturers (OEMs) and the lubricant suppliers have developed new and better products to give fleet users the benefits of extended service intervals, while at the same time maintaining equipment life and providing the potential for reduced operating costs. Through the selection of proper lubricants, fleets can now minimize their total operating costs with products that meet the OEM extended service specifications, have demonstrated equipment durability, and are formulated using base oil and additive components to minimize the cost of the lubricant.

This paper will examine the options available for formulating extended drain transmission and axle lubricants. It will explore the selection of the lubricant base oil as well as the additive system. Bench test and field test data will be compared for four products designed to meet the OEM extended service interval requirements using vastly different formulating technology. The results show that through an optimization of the base oil as well as the additive system, both synthetic- as well as mineral oil-based products can give acceptable extended drain performance. With mounting economic pressures in the trucking industry, these new products will give maintenance personnel additional choices as they move their fleets to extended drain transmission and axle lubricants in an effort to safely extend equipment life and reduce total fleet maintenance costs.