I think I've tracked down the odd Ggrrrring sound on my truck, looks like the xfer case front output shaft bearing is going.(from a too long ignored faulty u-joint) How hard a job is this one? any special tools req'd?

no special tools but special case sealer required, and case halves must be ABSOLUTELY CLEAN or it may not seal up. Not too hard just work from back of case towards front. There are 2 caged needle bearings for output shaft,1 front and 1 rear plus torrington type thrust bearings