Every time I shift my 07 manual transfer case from 4L to 4H it grinds going into high. I always put the automatic transmission in neutral and I've tried it while stopped and, slightly rolling. I've also tried waiting in neutral, stopped for 30 seconds thinking that gear was "coasting" and would eventually stop. No go. Am I missing something here?

 

When I shift trucks that have the manual transfer case I go from 4L to 2H/4H in one swift motion. I don't sit around in N or else some of them grind like that.

 

That gear is really spinning fast though, and doesn't seem to slow down if you wait on it.