Replace you damaged or worn transfer case synchronizer assembly with this complete synchronizer assembly from DHD. This is the synchronizer hub assembly comes loaded with the blocking rings (clutch). Replacing this component will require transfer case removal and disassembly. Related seal kit for assembly: DHD 100-263.
GM NP261XHD or NP263XHD transfer case found in 2001 to 2007 GM Duramax vehicles.
Note: If your truck is struggling to complete a mode shift, 4wd to 2wd or vise-versa, there's a good chance this could be contributing to the issue. Worn blocking rings will increase the length of time required to make a shift and/or cause grinding during the shift.