Are the lines to the tranfer case crossed? I am not certain if you can do that at the case but you might want to double check the inlets and outlets at the control valve assembly. Yes, that is the one in the rear with the nitrogen cell affixed to it. Two switches and one sensor are also attached to that valve assembly.
If you need some more info..........let me know.
I spent some time with that system.................your reman case could also be the problem but lets focus on the basics.