Thanks for the quick replies and tips......please keep them coming. The flex discs and driveshaft bearings are about a year or so old, as is the diff mount and motor mounts, but I will check them as well as the shaft and bearing. If it is a bad part I hope it is only the shaft and not the bearing. Any idea why applying the brake or adding power makes the noise disappear, or why it only happens at that limited speed range with no vibration?