I had this issue... and then I fixed it... and it is starting to come back. Here is what I've done so far:
Initially both front coil overs were making that old, wooden ship creaking sound. It drove me so crazy I didn't drive my truck for three days till I had time to figure it out.
What I found was that the outer coil spring was rubbing the inner back piece that is on the shock body. At first I thought it wasn't rubbing... but I found that it was when there was any kind of compression or the wheel was turned either direction. If you look really closely... I mean get in there with a flashlight with your eyes close... you'll see where the spring is rubbing on the black piece of the shock body. There will be some light scuff marks.
To fix this... I rotated the coils around the shock body to different positions. Honestly my rotations were mostly educated guesses on which position of rotation would cause the least amount of rubbing. The sound comes from the "metal" coil rubbing the inner black "rubber". You'll be able to tell the starting position from the new position by looking at the bottom of the coilover. I looked at the "tail end" of the coil itself to judge how far I had rotated.
1,500 miles later after I fixed my sound issue.. I am getting a small noise coming from my driver side coil again. This side was always worse than the passenger size. I can only hear it at low speeds when my steering wheel is turned at a certain degree.
It sounds crazy... but I honestly might get some mole skin, yes the kind meant for the human body, and put it on that spot that is rubbing. This might be a horrible idea.. but in my mind it will prevent the metal from rubbing on rubber... thereby getting rid of the sound. Lol.
lmk if that helps.