Transmission Problem

[dubmatic]

I was swapping out my transmission for a newer 4spd of of an 80's fj40 she seems to slide 80% of the way into the motor but I can't get it in all the way there is about a 1 1/2 gap all around. I was fussing around with it for a couple hours last night and got fed up and had to stop.

Not sure whats stopping it
Reason for swapping was the other t-case was stuck in 4 wheel drive. Also this one has been modified for 2H, 2L, 4H, 4L