Can you mix synthetic transmission fluid with regular transmission fluid

So, in the end, conventional and synthetic oils are comprised of the same, compatible components – it's just that the components in synthetics are much higher quality. While you can safely mix synthetic and conventional oils, you're doing nothing more than diluting the performance of the synthetic oil.

Each vehicle has specific transmission fluid requirements, so you should not mix transmission fluids. The type of transmission fluid specified by your car's manufacturer is based on a number of factors, including the transmission itself, operating temperatures, and service life expectancy.

With their improved resistance to the heat and cold, as well as sheer and oxidation, many manufacturers have already discontinued organic-based compounds in favor of synthetics. Synthetic automatic transmission fluids also tend to last longer, making them the overall recommended choice.

The most common situation where the wrong transmission fluid is used is in the case of using automatic transmission fluid in place of variable transmission fluid and vice versa. Adding ATF to a to a CVT will eventually result in the death of your transmission.