Hey guys,
Shimming tightens the LSD up and is nothing to do with the backlash, the diffs would need to be adjusted to take up the slack, if you dont know what you are doing just take the centre to a diff guru
If i was in Canberra i would help but 4hrs is a bit far for a quick look!
He is referring to a mechanical diff centre i would say, a lot of fun but they do clunk and carry on in carparks as they are basically locked anyway....
You should be able to check the diff bushes, subframe, tailshaft, gearbox and engine mounts etc man...... Its hard to picture what is happening from your description though......