Yes. You can add transmission conditioners without consulting a professional by following the instructions written on the bottle. There are a few general rules that one must follow and those include warming up the engine beforehand and making sure that the amount used is enough. Some vehicles may require double the dose due to their size. It also recommended to go for a drive after adding the additive. This allows you to test out the gears. Some treatments take around two days to complete their conditioning and restoration process while others may take longer. It all depends on the formula and the ingredients used.