2005 gmc 1500 4x4 trans. Makes a clunking sound when shifting up or down in all gears or when stopped going from forward to reverse. Sound is coming from trans. I layed under truck while my wife changed from forward to reversr and back again

 

im no professional but it maybe a universal joint in the drive shaft if that aint it, it maybe the splines on your tail-shaft or yoke wore out...or worse case scenario the chain in your transfer-case is loose....hope this helps