Greater towing capacity, less gear lube
Whether hauling heavy tools and equipment to a job site or towing a boat for a relaxing weekend on the lake, many vehicles are subjected to extreme operating conditions and hot temperatures in the summer, placing an increased level of stress on drivetrain components.
The extreme pressures and temperatures generated by modern vehicles increase stress on gear lubricants and can lead to a serious condition known as thermal runaway. As temperatures in the differential climb upward, gear lubricants lose viscosity and load carrying capacity. When extreme loads break the lubricant film, metal-to-metal contact occurs, increasing friction and heat. This increased friction and heat, in turn, results in further viscosity loss, which further increases friction and heat. As heat continues to spiral upward, viscosity continues to spiral downward. Thermal runaway is a vicious cycle that leads to irreparable equipment damage from extreme wear, and ultimately catastrophic gear and bearing failure.
In addition, some vehicle manufacturers require the factory-fill differential gear lube to be changed within the first 3,000 miles, or the first 500 miles if towing, a fact not known by many consumers. Because differentials go through a break-in period and are not equipped with filters like transmissions and engines, the gear lube must be changed in order to drain the break-in wear particles. These particles, if left in the differential, mesh between the gears and cause gear or bearing wear. Recent studies show that most differential wear occurs in the first 5,000 miles.
Bottom line: Use a high-quality synthetic gear lube to maximize your truck’s ability to tow and haul.