Warm rear diff

Been chasing a vibration on my 200tdi for a couple weeks now. Think i have pinned it down to the rear diff. The nose where the prop shaft is attatched feels warm after a run though the whole of the main casing feels cool. What does this indicate could the bearing that i assume is there be worn.
Cheers

could be if you remove flange and seal you can pull inner part of bearing out and look at the race in the casing