2003 Durango, 4.7L, 4wd.

I replaced the NV233 transfer case with a used one from ebay because my old case cracked. Now the the Service 4WD light comes on. I had to use my old motor with the new transfer case because the connectors were different. I didn't have issues with the motor before. I'm fairly sure the connectors are back on good. Any ideas what might be wrong?

Thanks, Danny

 

From what I have read this seems to be an electrical issue and not a mechanical issue. I assume it is safe to drive, I just won't have 4wd. Am I correct?

Thanks!