When dealing with different transmissions that didn't come in a 4x4 you have to make thing's work, I have seen some with the same problem you are having. Some as only one drop on the cross member and that's the ones that go with a 400 trans and it's on the passenger side and some have to put spacers between the crossmember and the frame to get the trans mount to work. The ones i've dealt with the trans mount bolts to the adapter between the trans and the transfercase. If it all didn't come from the factory that way you'll have to just make it work.