1977 np205 speedometer cable not fitting

[cj4life]

Hey guys, so im trying to hook up my speedometer cable to my NP205 transfer case out of a 1977 k30. only problem is my cable will not fit. It threads on just fine, but the cable it self doesn't seem to fit. the cable is square and fairly long, but the input for the transfer case tip is round and extremely shallow, like centimeters deep. my question is, do I need an adapter, different cable, or different driven gear, can i just shorten it? what do you guys think?
Thanks

[rich weyand]

The socket for the speedometer cable on the transfer case is round?  Are you sure?  Should be broached square internally, though it looks round right at the end.  Get a flashlight in there and check.