Transfer case hitting bottom of cab???

[kxnomore]

I just re- installed my transfer case today, and the top of the transfer case is now hitting the bottom of the cab floor. I did get a new to me crossmember out of a used truck, as my original crossmember had been bent. My truck is a 72 K10, and I am not sure exactly what year or style of truck the crossmember came from, but they looked identical. Is there a difference between a 3/4 ton transmission crossmember and a half ton crossmember (4 X 4)? Also, the torque support bolt holes for the transfer case don't line up anymore, and it looks to be about 3/4 of an inch below the current transfer case location?
It seems to me that I must have gotten a 3/4 ton crossmember, and they are not interchangeable. Anybody know for sure?