94 Bravda Awd Need Help

My 94 Bravada is making a loud clunking sound when you put it in gear and take off fast. (if you start out real real slow and build up speed it will not make the noise for a little while) Its coming from the transfer case area, like maybe the front drive shaft. Does anybody know if the CV joint on the front drive shaft can be changed or do you have to replace the whole shaft. It has around 115K miles on it and it just started making the noise one day. Any ideas or suggestions??
Thxs
Rick

Do you have a humming noise coming from the front when you let off the gas and slow down, this is without applying the brakes? I think you may have a wheel bearing hub assembly problem. Check some of the other posts on this site. Also do you get the same clunking sound when you make a sharp turn at low speed, ;ike when you turn into a parking space?