hard to say...
I know many owners of the local boneyards,I dealt with them often when I worked at one of them...they give me good deals on parts,but if I were to bring them something to "trade",I am not sure if they would go for it or not--maybe if I was trading a good engine, they would give me something worth half as much,if that..they buy whole cars for less than 100 bucks,and turn around and sell an altenator and scrap the catalitic converter ,and they are ahead of the game..to them,its just an engine--they look at it as scrap,no matter how good it might be..(until someone wants to buy it--then suddenly its worth top dollar!)..
Most of the yards here have so many cars and trucks and such a high volume,they literally give stuff away cheap,or simply crush it,since its 110 bucks a ton now..they probably would only pay you scrap value and nothing more for items you wanted to trade...yards here are looking to make money,not trade stuff for the most part..since I know the owners well,they might make an exception if it were me looking to trade something..I have GIVEN them junk cars when scrap was only 10-15 bucks a ton,just to get rid of them!--they remember that when I come looking for parts later!..
If the transfer case you dont need is a desireable one they know they could sell easily,and the one you need is a "dime a dozen" variety,they might let you swap it for the one you need..only way to find out is to ask..
I asked around at the boneyards if anyone wanted to buy my 79 C10--they all said the same thing..drive it on the scale!!

---no thanks,I'll keep it if all I can get is 250-300 bucks in scrap for it--no sense in crushing a decent truck--I'm not THAT desparate for cash yet--but I might be soon!
