US Lube LSD Syn FE Gear oils are formulated using only the fully synthetic base stocks with the high tech, EP additives. Compounded with advanced sulfur-phosphorus extreme pressure additives, US Lube LSD Syn FE Gear oils are designed to meet the severe lubrication requirements of modern passenger cars and truck axles, especially those with hypoid gear sets. Due to the excellent characteristic of the synthetic base stock, US Lube LSD Syn FE Gear oils exhibit less deposit formation, less viscosity changes during operation and more stable performance in extreme pressure properties if compared with the conventional mineral gear oils. Furthermore, US Lube LSD Syn FE S5 Gear oils also provide much enhanced fuel economy and extended drain interval over other same visco-grade gear oils. Although it can fully compatible with other mineral gear oils, it is good practice not to use US Lube LSD Syn FE Gear oils with other gear lubes, since it may reduce its advantages.