Truck Forums - Rear spring noise?

Last fall I bought a 99' F-150 ext. cab with about 118,000 miles on it at the time. Really the only complaint I had at the time was that somewhere in the back right axle when it goes over a bump there is a loudsqueak. The dealer said it was from an older gentelman who had let it sit a while. http://tractors.myfreeforum.org/imag...smilies/bs.gif I thought running it around awhileMIGHT knock the rust out of it and be fine. It kept the squeak all through the fall but as the tempurature got colder it went away. Well now that the weather is warming up it has gone back to making this noise again. Has anyone else had this problem? It is very noticable when driving at lower speeds like in a parking lot (10-20 mph). I really don't want to get new springs,shocks, etcas a shot in the dark method, but I don't know how I can find it without it moving. I've already put oil all over the springs....