Title says what my problem is. I had a bitch of a time getting the old one out, and now I'm having trouble threading the new one in. Is there a trick to it?

 

I can't think of anything unique about installing it off the top of my head. The transfer case was in 2wd when you removed it, yes? The only thing I could think of is if it was in 4HI when you removed it the shift fork will be in the "up" position which would push on the spring loaded ball end of the vac switch. But I don't know if it would be high enough to prevent any threading without downward pressure.

 

No...it was me freezing fumbling fingers that were the problem. 3 hours of shoveling snow before I decided to take care of it. After having a bitch of a time removing the old one I was trying to screw it I to a depression in the top of the case and not the actual threads Needless to say I couldn't see what I was doing and my fingers were effectively just as blind. After I posted I took the time to warm my hands up a bit and was done in a couple of minutes once I climbed back underneath.