75w90 Synthetic Gear Oil 1 Qt

The Lucas Oil 75W90 Synthetic Gear Oil is engineered for serious vehicle builders and mechanics who demand reliable protection in high-stress drivetrain applications. This 1-quart bottle delivers premium synthetic lubrication for rear differentials, transfer cases, and manual transmissions across trucks, SUVs, and performance vehicles. Whether you're running stock gears or pushing modified ratios, this gear oil maintains viscosity stability across temperature extremes while reducing friction and wear on critical components.

The 75W90 viscosity rating delivers cold-start flow characteristic of a 75-weight oil while maintaining 90-weight protection under highway and track temperatures. Lucas Oil's synthetic formulation resists breakdown from shear forces generated by hypoid gear mesh, oxidation, and extended service intervals—critical when running modified gearing or aggressive driving. The formula includes anti-wear additives and friction modifiers that reduce churning losses while protecting thrust washers and bearings, ensuring smooth engagement and reduced heat generation even in limited-slip differentials.

This product suits truck owners, off-road enthusiasts, and performance builders working on lifted suspensions, regeared axles, or manual transmission swaps. Use for rear differentials (open or limited-slip), transfer cases on 4WD systems, and helical gear manual boxes where OEM GL-5 or GL-6 specs apply. The 1-quart format allows precision top-ups during maintenance or full changes; always verify your vehicle's manufacturer fill capacity and drain intervals before service.