Gear Oil Is A Lubricant Used Specifically For Automotive Manual Transmissions For Cars, Trucks And Different Types Of Machinery. It Has A High Viscosity For Better Performance And Protection Of Gears. Lubricants Designed For Manual Gearboxes And Differentials Are Also Called Hypoid Gear Oils. They Offer Higher Viscosity To Protect The Gears Better. The High Viscosity Ensures The Transfer Of Lubricant Through The Gear Train, Which Is Essential Since Devices Needing This Heavy Oil Do Not Have Pumps For Transferring The Oil With Only A Part Of The Lowermost Gears Bathed In An Oil Sump. This Heavy Oil Can Create Viscous Drag, Leading To Inefficiencies In Vehicle Operation.