The Right Tool for the Job
Today’s vehicles produce substantially more horsepower, torque and towing capacity than their predecessors, yet the design of differential gears and bearings remains largely unchanged. Many differentials even use less gear lube and lower viscosities than before in an effort to reduce drag and increase fuel economy. In essence, less gear lube is responsible for providing more protection.
Fighting the Grind
Differential designs have inherent weaknesses. In a traditional automotive differential, the pinion gear concentrates intense pressure on the ring gear. As the gear teeth mesh, they slide against one another, separated only by a thin layer of lubricant. The repeated stress the lubricant film bears can shear gear lubes, causing permanent viscosity loss. Once sheared, the fluid film weakens, ruptures and allows metal-to-metal contact, eventually leading to gear and bearing failure. The situation is amplified by severe-service applications like towing.
Thermal Runaway
The extreme pressures and temperatures placed on gear lubricants can lead to a serious issue called thermal runaway. As temperatures in the differential climb, some gear lubes 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.
AMSOIL SEVERE GEAR Synthetic Gear Lube
SEVERE GEAR excels in protecting gears and bearings from the rigors of severe-service operation. By design, it resists breakdown from high heat, preventing acids and carbon/varnish formation. Its wax-free construction also improves cold-flow properties, improving fuel economy and cold-weather performance.
- Superior film strength
- Controls thermal runaway
- Protects against rust and corrosion
- Helps reduce operating temperatures
- Maximum efficiency
- Long oil, seal and equipment life
- Flexible easy-pack for clean, fast installation
- Ultimate Cold-Weather Protection
Some gear lubes fail to meet basic low-temperature requirements. Mobil 1* 75W-140 Gear Oil, for example, failed to meet the requirements of the industry standard1. AMSOIL SEVERE GEAR, on the other hand, delivers 20% more cold-temperature protection than the standard requires. It delivers better cold-temperature protection than Mobil 1 and Valvoline* SynPower*.
1 Based upon results of samples of Mobil 1 75W-140 and Valvoline SynPower 75W-140 purchased in 2018 and tested in ASTM D2983 by an independent testing facility in May 2018. Samples sent blind to eliminate bias.
*All trademarked names are the property of their respective owners and may be registered marks in some countries. No affiliation or endorsement claim, express or implied, is made by their use.
