Is There a Difference Between Transmission Fluid and Engine Oil?
2 Answers
Transmission fluid and engine oil are different. Although both serve a lubricating function, these two fluids perform distinct roles and should not be confused. Specific differences: Engine oil is a lubricant for the engine system, possessing properties such as oxidation resistance, wear resistance, and corrosion prevention. Transmission fluid, on the other hand, is primarily used to keep the gear system clean and extend the service life of internal transmission components. Due to the differing structures and operating environments of the transmission and engine, transmission fluid cannot be used as engine oil, nor can engine oil be used as transmission fluid. Functions of transmission fluid: Reduce friction and wear, control clutch friction and synchronizer performance. Load-bearing (low-speed high torque, vibration loads), heat dissipation, vibration and noise reduction, and removal of contaminants at gear meshing points (cleaning function). Prevent corrosion, pitting, and surface metal tearing, isolate metal surfaces, and prevent direct contact between metal bodies.
As a veteran driver with twenty years of experience, I clearly understand the difference between transmission fluid and engine oil. Engine oil primarily lubricates internal engine components, such as pistons and connecting rods, and it must handle high temperatures and impurities from combustion, so it contains cleaning additives. Transmission fluid lubricates gears in manual transmissions and also acts as a hydraulic fluid for gear shifting in automatic transmissions, with a greater emphasis on maintaining stable friction. The formulations of these two fluids differ, and their viscosity grades are not the same—using the wrong one in the wrong place is asking for trouble. I remember when I first bought my car, I mistakenly added engine oil to the transmission, resulting in jerky gear shifts and a repair bill of several thousand dollars. Now, I strictly follow the manual and change the transmission fluid every 40,000 kilometers to ensure smooth and safe driving. Neglecting this can lead to serious transmission damage, and the cost is far too high.
