I am driving an 84 300D and am trying to diagnose a sound I hear and feel in my drive train. I feel a bit of a rumble from the rear when I am slowing down and almost stopped. It kind of feels like gears changing with too much play. I got under the car and looked at the flex disks and they look almost new. I concluded that the PO changed them relatively recently. Also, when I am cruising along at a relatively low speed, say 25 mph, if I hit on and off the gas pedal, I can feel a most definite play in the drivetrain. Could this be gears in the differential that are worn out. My next inclination is to empty the diff and take off the cover to have a look. What should I be looking for?

Thanks for any input.

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