Rear squeak from shackle.

Hey I was wondering if anyone had an issue with a rear squeak coming from the rear linkage? I replaced the suspension all around on my truck last year new shackle and bushings. I had this all done because I wanted a better suspension and to get rid of the sound. It worked up until a month ago and started squeaking again bad. Its been a year so the parts aren't warrantied. I greased them up and removed the bolts to spray it down and let it seep in but hasn't made much difference. Anyone have a similar issue and found a good way to fix it with out replacing the shackle and bushing again?