i have a transfer case 231d that broke and I am having a hell of a time finding one and was wondering can you use a transfer case with different spline if not can I use my spline from the old one on the new one ?

 

the tcase spline count and the drive shaft spline count need to match.

 

--- and swapping the front end to use your old input shaft on another t-case is difficult, not recommended. Find the right one and bolt it in.

Define 'broke'. Other that that front spline shaft, the rest of the t-case is easy to repair.