P38 Diff Flange

Hello,
today i have changed the shock absorbers of my range and see, that the front and rear diffs are leaking.
What is the best way to repair?
To take an diff flange and seal kit like this:

Range Rover P38 Diff Flange & Seal Kit bei eBay.de: Land Rover (endet 06.03.11 16:45:25 MEZ)

or only to change the seal like this:

RANGE ROVER P38 AXLE DIFF PINION OIL SEAL bei eBay.de: Land Rover (endet 28.02.11 16:01:10 MEZ)

My local landrover dealer tell's me, that it is the best way to change the full system, because the diff flange can be have abrasion.

Regards
Range0815

remove flange and have a look, brgs have shims to attain preload so you only have to get flange bolt or nut tight,some flanges may well have pitting were seal runs but most are usually fine