Here's a trick I've used when diagnosing oddball suspension problems. Connect a cable "come-along" to the rear axle tubes one side at a time, and try to pull the axle housing forward and back by hooking the ratcheting end to a frame crossmember. It can pinpoint sloppy bushings that need more force than a pry bar to cause things like the trailing arms to move back and forth. I've also seen suspension noises come and go with rainfall- - - - -when the undercarriage is wet, there's no noise, but when things dry out the noise returns. Good luck!
Jerry
