Categories: HFRR EHD

Gear Oil Additive

Gear oil formulations comprising a gear oil and a film forming agent are disclosed. The film forming agent comprises a polymeric ester which is the reaction product of at least one polyfunctional alcohol, a dimer fatty acid, an optional aliphatic dicarboxylic acid having 5 to 18 carbon atoms and one or more ingredients to reduce the acid value of the polymeric ester to below 5 mgKOH/g with the resultant polymeric ester having a kinematic viscosity at 100° C. ranging from 400 to 5000 mm2/s and a weight average molecular weight ranging from 5000 to 20000. When used as an automotive gear oil formulation the specifications for API GL-4 gear oils are at least satisfied. Use of the gear oil formulation in manual transmissions, transfer cases and differentials and use of the gear oil formulation in an industrial gear suitable for lubricating spur, helical, bevel, worm and hypoid gears are disclosed. Methods of lubrication are also disclosed.