I know this sounds stupid, really stupid, but do you have an aftermarket front bumper? So...my story...
I built my bumper and had no issues for about 3 months. Then noticed a clunk in the front end. Checked it all out myself, replaced a few items (including both CV shafts) and still there. I had done the frame clearance cut, so I replaced the cab mounts for GP even though they looked fine. Still there. I pulled off the cheap skid guards...still there. Finally got pissed and took the front bumper off...gone. Noticed some fresh steel in the mounting holes, yet the bolts were tight. Since they are slotted, I filled in the excess space. No more clunk. The bumper was flexing with the frame when I turned hard or accelerated hard from a stop. So if you do have an aftermarket bumper, pull the bolts and check for wear, could be the same issue.