Motor oil and transmission oil or fluid are needed for basic car maintenance. There are several differences between the two, and each is designed to serve a particular purpose for the car.
Although both motor oil and transmission fluid (oil) are designated to cool and lubricate, only transmission fluid must be constantly under pressure. Furthermore, motor oil also cleans and protects the engine, while transmission fluid provides shift control.
Motor oil is designed to lubricate the moving parts inside of an engine to prevent metal to metal contact. Additionally, it is intended to keep engine parts cool and clean the engine of waxes, carbon deposits and tar naturally found in oil. Transmission fluid also lubricates and cools moving parts; however, it is a thicker fluid that delivers power from the engine to the transmission.
In motor oil, additives such as detergents, buffers and solvents are added to keep the engine clean from deposits. Although transmission fluid is similar to motor oil, it is intended to be used in the hydraulic system of a vehicle. Corrosion inhibitors, polyalphaolefins (PAO) and esters are some additives included in transmission fluid to make it last a long time.
