I got under there with a mechanic stethoscope and it is for sure more prominent from the mounting locations than anywhere else (shock tube, shackles, leafs etc) and on one I can hear a little bit of squeak sound like you're stretching a thick piece of latex or something. Would the IFP make noise on up and down travel though? I could be wrong, but to me it should only (potentially) make contact when the shaft is nearing full extension, not under compression as well. When I step in/on the truck slowly it makes a kind of groaning sound the whole way. Similarly, if I then lift up on the truck from the rear hitch for example it makes the sound during the trip up. It's not a single clunk on either end of the movement. The sound is also coming from both shocks, although, yes, I rebuilt both the same way. But I didn't touch the bushings.