The early LSDiffs (up to #9000 I think) had a problem of clunking. I noticed thios with last car (build May 2000) but has gone with current one (March 2001).
For mine it happened first in a carpark. To get it to repeat, I did 3 turns full lock at about 5 km'h one way, then repeat opposite direction. It would clunk like a lock in 4wd diff on tarseal! It got so bad at last time rear end would clunk around 90 degree corners. Oil was changed 3 times, and an additive added. Diff went quiet for next 5000km until car went away and new one came.
AUIII XR8, Manual. Herrod Motorsport bits