well if its is a grindy noise, then I dont think that the outlook is flash. You can either replace the box, which is an easy job, or just be gentle with it, and hope that it keeps on hanging on. Probally the best option if you dont drive far from a workshop or home, but if you travel a bit, then replacing it will put your minid at rest.
Me I would just put up with it, as I dont travel far, and I have 3 spares.