The difs seem to have some problems for some people, difficult to actually get metrics on it b/c the internet tends to draw out a lot of 'my difs are whining, the dealer wants to replace, it's $$$!' threads but nobody posts 'I drove my truck past 100k today and there is nothing to talk about'.
I drove my 2005 LR3 past 135,000 today, and there is nothing to talk about. (Knock on wood.)
I am the 3rd owner. PO bought it with very low miles and certified with extended warranty, so all the dealer maintenance had been done. All the same, Diffs aren't on the maintenance schedule until 100k or so.
I changed my diff fluids right away (at 90,000). then again a yr later to make sure no cruft had accumulated. Then again another yr later, to make sure the previous time wasn't an aberration (and it's not too difficult). Fluid and magnets looked good, so I'll let it go a couple years before next change.
The drive train has been fine for me.
I also had the powerflush done on the tranny right away. Lots of passionate opinions as to whether powerflush or drain-and-replace-pan is preferable. It's a pain to drain (you have to lift the engine and remove the pan), and the guys on the English Disco3 forum seem to mostly go with powerFlush, and the local indy mechanic recommended powerflush and it's 1/2 the price, so I want that route. It's still smooth and strong. I'm planning for another powerflush within the next 5k or so.
Good luck!