Due to popular demand, the automatic transmission is far more commonly used in modern automobiles than the gearbox designs of the past. Most consumers will no longer tolerate these traditional, manual transmissions which require the constant labor of shifting with a clutch and lever. The automatic transmission is the primary source of power distribution between the vehicle's engine and it's wheels. Because it is used in the large majority of modern automobiles, both it's importance and complexity grows with each new vehicle model's design and production. The automatic transmission fluid used in these designs is no different. The many roles of lubricant, coolant, and hydraulic fluid require it to be as complex and precise as the component itself.

Automatic Transmission fluid, most simply, acts as any other oil in lubricating vital, internal parts from unnecessary metal on metal wear. The heat and friction created from gears and shafts during transmission use is often extremely intense. This means that it's durability, viscosity index, and capacity to withstand those stresses between drain intervals must be more than just competent. Besides lubricating the internals of an automatic transmission, it's fluid must flow through external lines to the vehicle's radiator to be cooled and return to cool the component as well. Along with these other important roles, automatic transmission fluid must act as a hydraulic fluid, transferring engine power from the torque converter and throughout the many tiny passages in order to complete smooth gear changes or shifts. The ability to perform all of these tasks at once requires a complexity like no other automobile component fluid.

This complexity requires low volatility, precise viscosity levels, low compressibility, and a low foaming tendency among it's many other requirements. These qualities are most easily found in the synthetic fluids created by engineers for superior, molecular uniformity and stability. Synthetic automatic transmission fluid can be created more specifically than conventional, petroleum based oil for it's wide variety of required tasks. They also hold higher durability ratings and contain special, friction modifier additives which help performance under extreme stresses. Synthetic products, such as Amsoil's synthetic universal automatic transmission fluid, can be used in a large number of vehicle applications and produce far better results than conventional, mineral based fluids. It provides higher levels of thermal and hydraulic stability and performs better under extreme, external temperature settings. Synthetic, automatic transmission fluid is quite simply a better application for the newer, more complex automatic transmissions currently being produced for consumer satisfaction.

Most vehicles built today use an automatic transmission rather than a manual gearbox because of higher consumer demand. Their design is becoming increasingly smaller and more complex to deliver smoother shifts and higher performance. The automatic transmission fluid used for lubrication and hydraulic purposes in these designs has become more necessary for their protection and correct operation than ever before.