Hi
I've rebuilt mine, albeit a separate Lt85/LT230 combination, all using parts from Ashcroft transmissions, they sell rebuild kits.
I also put into new thrust washers and a one piece centre pin for the centre diff even though it was ok. As I understand it this part is the pretty much the only weakness in what otherwise is strong & reliable transfer case design.
Clive
Ashcroft Transmissions - HD Cross Pin

