It is a backup warning system. Every time you put the car into reverse and let off the gas it "tinks" to let you know that the vehicle is moving backward. Attempts to override this warning system by replacing the driveshaft have proved to be futile.
The only known cure is to either put on earplugs or turn the radio up louder.
The only known cure is to either put on earplugs or turn the radio up louder.