Faulty sensor somewhere? Your seat belt buckled? All the lights in your cluster work? If a light is burnt out (or removed by a previous owner) you might not be seeing an indication to go along with a noise like that.
2000 Mustang GT Steeda #0048 34k miles. 99 Cobra 4V swapped, FTBR IRS swapped, exhaust, tuned by James Gordon.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.