Bought an exchange diff with upgraded bearings from We Are Diffs (ebay) and had it fitted a couple of weeks ago.

WOW! What a difference, the noise I thought all tractors made, has now gone!

Bought it with the Haldex service kit, so there's a little more peace of mind.

Its suprising how one gets used to the noise. Now you can hear all the other parts that need attention! I fixed most of the worn parts on our Discovery TD5 a few months ago, my wife refused to drive it because it was a differnt car to her.