vehicle has been vibrating at low speeds when turning or when backing up. Took vehicle to BMW dealership (BMW of Nashville in Franklin, TN) multiple times during the past 18 months without resolution. On my visit for the same issue this month, dealership finally recognized the issue and said there was a BMW bulletin out about the issue SIB 27 02 20. It is very frustrating that 1. The dealership kept stalling and despite test driving the car with me and feeling the vibration, they kept blaming tires or saying it was normal while the bulletin about the issues was generated in 05.20.2020 2. It cost me over $627 for them to change the transfer case oil to diagnose and repair the issue. I am still in the testing phase after the transfer case oil change as the vehicle needs to be driven 300+ miles. The dealership and BMW should issue a recall since it is a know issue that the wrong oil was used in the manufacturing process and reimburse the cost charged for diagnostic and transfer case oil replacement. The vehicle is furthermore still under warranty so I should not be paying anything for diagnostics or repairs.