Is transmission oil and engine oil the same?

Answer 1

"NO, they are NOT." ... (supervisor)

Of course they ARE DIFFERENT, but not saying anything about the difference don't helps in any way.

previous answer by Amclaussen:

The lubrication, cooling and friction characteristics of an internal combustion engine and a transmission are completely different. Transmissions require a quite different lubricant than those used in engines. Manual transmissions require a GEAR type oil, whose viscosity is higher than the range of viscosity of motor oils, and there are some EXTREME PRESSURE additives in most gear oils, which are not used in IC engines.

Automatic transmissions use a Transmission Fluid, not oil; called "ATF". Even different make of cars can require different ATF's: Chryslers for example should use Chrysler's own ATF, called ATF+3 or the newer ATF+4, which is somewhat different from the usual DEXRON or MERCON type used by other American cars.

Additional info:

The internal combustion engine in a car has verydifferent requirements from those of the transmission. In both uses there is a need to LUBRICATE, cool, reduce wear and to cushion mechanical shock... but in the engine there is a need to help seal the piston rings. There are two different requirements in regard to oil viscosity, operating temperature and the presence of combustion byproducts like water or unburned fuel in the crankcase of the engine versus the transmission.

In the case of a hydraulically operated Automatic Transmission, the transmission of power through a fluid is a quite different requirement, therefore those use what is called an "Automatic Transmission Fluid" (ATF) and NOT a transmission (or gear) OIL. As a result, motor oil and gear oil are not the same, and an ATF is even more different.