there easy to pull out.
but i heard they are a bit tricky to weld...
anyway
1. jack car up and put on stands
2. take wheels off and take axles out
3. un-do tail shaft bolts that conect to diff and let it drop.
4. un-do all 8? bolts around diff centre
5. un-do drain plug and drain the oil
6. take diff centre out
7. give it a bit of a clean(dont use degreaser as it will f*** your bearings)
8. weld the small cogs together in the very centre of diff
9. clean it up again (all the slag etc)
10. put it all together opposite to how you pulled it apart.
this is a quick post. but im sure there is a more detailed thread in the tech section
lol
cheers
ps. this should be in another section.