Anticipating this was done, what about the CV,s and bearings in both CV shafts , if thats what they are, or axles?
The rear shafts left and right have a CV joint either end, so there is 4 all up. It's possible that one could be noisy, a split boot would be what to look for as an indication of lost grease. Also would be wise to check that they are tight (no loose screws). The reason I suggested the tailshaft was because you can feel it through the floor rather than hear it at the rear end.The way to accurately diagnose it would be to have the car on a 4 post hoist, jack up both of the rear wheels under the lower control arms and have someone drive the car up to speed while another person is under the car listening for the location of the noise.I've had to do that on the odd occasion to locate strange noises in the driveline.Cheers Glenn
Thanks Glen, happy with your response. It might sound like I know a bit of what I'm on about when I take it to Holden.