Smoker,
On my 1990 W-350, that I converted from Getrag to 2000 NV 4500 the transfer case adapter which is bolted onto the front of the NP205, was used on both types of transmittions with no modification. When we swapped transmittions all we did was pull out the trans. case, getrag, stock bellhousing..... bolt up the Advance Adapters bellhousing, bolt up the NV4500 (after modifying the front bearing retainer and changing the input shaft) , modified the crossmember slightly(Advance sells one for about $40) and bolted up the transfer case & drove away. Different years may vary, I dont know, a quick call to Advance Adapters in Paso Robles, CA. would probably fill you in on what you need to know. I'm not affiliated with anyone and I dont have anything to sell unless you need code quality pipe welding & fabrication but we did recieve good service from them and some days thats hard to find. Also, the coupler between trans & transfer case was reused from the getrag. I didnt have to modify my driveshafts but I understand some people have to. The backup light connection from the getrag won't plug into the 4500 but thats all I can think of, good luck,JTMcC.