The symptoms you describe are the diff, especially the clicking around slow corners, it's worse when hot as the oil is even thinner, diff oil changes are often overlooked during a service because of difficult access, you may potentially have 10+ year old oil in there
Make sure the new stuff is a known brand and states LS grade (for limited slip)
If you are going to attempt yourself, DON'T drain it until you have tested you can get the refill plug out which is hard to access, on the back of the diff case about half way up
