My D2 V8 had a rumbling noise. It has only done 117,000. The noise wasn't there under 80 and got louder as I accelerated past 80. Up hills it was even worse. But down hills it wasn't there at all. I have a hoist in my home workshop and so I checked all the wheel bearings. No wobble and not noisy. Checked all the universals, and that the prop shafts were sliding on the splines. Found nothing. But a last inspection before dropping it down and off the hoist and I discovered that a bolt was loose on the rubber coupling at the rear diff. Could not get the bolt tight so added a washer and now it is tight and the rumbling noise has gone. I have ordered a new coupling and will fit it as soon as it arrives.