Put your left hand on the parking brake release.
Back up and recreate the noise.
Press parking brake gradually. Use it to slow and stop the truck. Parking brake is a cable liinkage to the rear drums only.
Note change in noise or not.
Remove drums and verify proper installation of brake parts.
Look for scoring on the drum surface, loose parts, etc.
Did you see this thread? http://www.ranger-forums.com/forum2/...ght=rear+brake