1996 Eldorado Rear Suspention Squeak

Hello i have a 1996 eldorado and its in good shape jsut got a problem with rear suspention looks evertime i drive with the windows down to find out whast the probme i hear it coming from the back end of the car and it sounds like a squeaking sound everytime i hit a bump or the road is wavy i hear it ever time the car gos up and down also hear like a cluck sound like if someone would be lose those are the 2 noise if anyone ever had this problem please let me know what to replace.