Lucas Oil 75W140 Synthetic Transmission and Diff Lube is a pure synthetic gear oil. This super-slick, long lasting lubricant is designed especially for heavy duty or high performance applications where regular gear lubricants just aren't good enough. Contains a special additive package that increases lubricity and insures less gear noise and longer bearing life. Excellent for use in limited slip differentials. Designed to stand up to high temperatures without losing its lubricity.