Few questions for you.
If I read this right you are putting a gear drive T-case in front of your chain drive t-case?
Did you make sure the coupler is all the way in on the tranny? They are real tight and really have to be hit pretty hard. I used a block of wood and a 4 pound hammer.
Is the seal adapter seated all the way in on the adapter plate?
Did you do the grinding on the tranny as per instructions?