I think I may have an issue with the transfer case in my 03. When I put it into 4wd it just pops/snaps and the front driveshaft won't turn. Getting ready to tear into it, I was just wondering if anyone has had a similar issue. I have done some research and found some chain issues and something about a snap ring on the main/output shaft that likes to break and fall off, causing this type of issue. The truck is an 03 NV5600 with the NV271D manual shift. When not in 4wd everything seems ok, no noticeable noise or other issues.