small Clunk
 

On the same '93 GMC 1500, it's the Z71 4x4. There is a slight clunking when I'm driving it, you can feel it with your feet, and a little in the steering wheel. You can feel it in all gears and nuetral. I picked the truck off the ground and put it in gear letting the tires spin, the clunking wasn't there in 4 wheel or 2. It almost sounds to me like a brake dragging that has a warped rotor or something, or the driveshaft. Which or what else would you think i need to look at, and how can I figure out where it's coming from?