Gear lubricants automatic transmission fluids

The most common VI improvers are methacrylate polymers and copolymers, acrylate polymers (see Acrylic ester polymers), olefin polymers and copolymers, and styrene—butadiene copolymers. The degree of VI improvement from these materials is a function of the molecular weight distribution of the polymer. VI improvers are used in engine oils, automatic transmission fluids, multipurpose tractor fluids, hydrautic fluids, and gear lubricants. Their use permits the formulation of products that provide satisfactory lubrication over a much wider temperature range than is possible using mineral oils alone. 

Over the years, detergents have found equally important usage in many other types of lubricants, including gear oils, farm tractor hydraulic fluids, automatic transmission fluids and industrial oils. The performance properties that detergents impart to these lubricating fluids include rust and corrosion prevention, improvement in lubricant elastomeric seal compatibility, enhancement of sludge control under oxidative conditions and improvement of wet clutch and wet brake friction level and stability. 

Many applications of surfactants in lubricants and fuels have a common purpose, namely to reduce or prevent the formation of deposits by the degradation products of lubricants and fuels. In lubricant applications, surfactants serve in various roles. In crankcase oils, surfactants reduce and prevent sludge formation and deposit formation in pistons, cylinders, and valve train systems [1]. They also reduce and prevent sludge formation in the reservoirs of transmission fluids, gear oils, and industrial oils, and keep parts clean by prevention of deposit formation on metal parts. In addition, they provide friction control in friction interfaces as in automatic transmissions. 

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