I've got the same problem. My first thought was the speedo cable was bad, maybe. Either that or the cluster itself, Im gonna do a cluster swap with a 140 mph and see if it fixes it. Other than that, lets hope someone out there knows how to help us! It is kinda nice to know that its not just my car that has that god awful annoying noise.
Mine made noise too, I took off the cluster and unhooked the cable, pulled it out lubed it and no more noise, thats been about 6 yrs ago. Not a hard fix.