Need a decent used transfer case assembly

Shot how? You can refresh it yourself relatively easily for a lot less than buying another one, unless you physically broke one of the main parts.
 
It’s at a second mechanic. He originally thought he could fix/rebuild it. Yesterday he called and said it would most likely be cheaper to get a used one to put in it because there’s very little salvageable from the one in it. The issue had been it would not stay in 2wd. He said the prior owner had the wrong fluid in it and had rigged something to keep it going. I’m not sure what all needs replaced in it but i know the chain, the gears and the vacuum hoses were completely shot.
 
It’s at a second mechanic. He originally thought he could fix/rebuild it. Yesterday he called and said it would most likely be cheaper to get a used one to put in it because there’s very little salvageable from the one in it. The issue had been it would not stay in 2wd. He said the prior owner had the wrong fluid in it and had rigged something to keep it going. I’m not sure what all needs replaced in it but i know the chain, the gears and the vacuum hoses were completely shot.
Ah ok. That’s unfortunate. If you have no luck finding used ones, and if you can stomach the cost, RockAuto sells them remanufactured for about $850 once the core exchange is done. Otherwise keep checking eBay or maybe something local will luckily pop up. I barely ever see them for sale so I’d probably go the RockAuto route if that happened to me.