I plan to rebuild the one I'm taking out at leisure. I don't have time to be without a vehicle at the mo so a rebuild while its out is out of the question.
The R380 box is known for suffering massive spline wear on the input shaft from the transfer case. You can get round this by fitting a new part (actually in the transfer case as I recall) that has a cross hold drilled into the splines to allow oil in. It's very recommended that you do this.