It is generally not recommended to mix different types of transmission fluids, including Mercon SP and BMW transmission oil, unless specifically recommended by the vehicle's manufacturer. Each type of transmission fluid is formulated with specific properties and additives to meet the requirements of a particular transmission system. Mixing different fluids can alter their properties and potentially affect the performance and lifespan of the transmission.
If you are unsure about the appropriate transmission fluid for your vehicle, it is best to consult your vehicle's owner's manual or a qualified mechanic to ensure you are using the correct fluid and avoiding any potential issues.
