Torque and thrust arms are the first to cause problems, they are parts 10 & 11 in the diagram. However, after time the rest of the rubber does rot and disintegrate. Figure $800-1100 for a shop to replace the rear rubber complete (excluding the subframe mounts). The rear diff bushings and the support joints (bottom of the wheel carrier) are the hardest part of the job.

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Brian Toscano