My FG XR6T (manual, 23,000 on the clock) is at Ford as I write (for some warranty work). I told them about the noise and they were all over it - rear diff bushes I was told, and they are going to do it under warranty. Low and behold, im serching around on here and stumble across this thread... Im going to drop in before work tomorrow and quote them the part number for the new bushes (special thanks to those who dug it up!). If im having my back end pulled off, I want to make sure these new magical bushes keep it running smooth and quiet for more than 23,000km!!