Could be either the posi is going bad, or a carrier bearing. Coast at about 30 or so in 5th gear, and turn the steering wheel back and fourth, so the rear sways, then listen for noise. If the noise comes off and on, like you can bearly hear, then is a carrier bearing, you should be able to tell which one it is if your good
Othewise could be the posi. Only way to see whats wrong is to pull the cover off
