Outer Limits 4x4 Board

Just bought my first 4wd a 2008 Colorado. I took it out for its first run today and when I engage 4WD there is a clunking noise. The car went well and once engaged didnt have a problem what sort of issues cause this noise. Any advice would be appreciated as my mechanical knowledge extends to general servicing etc. Thanks Mick

If you use the shift on the fly to engage 4wd whilst moving you wont notice any noise. You should only hear a slight clunk when engaging 4wd low and this is normal.

Thanks for taking the time to reply. Its all good on the changes on the fly like you suggested.