Axle bearing going bad??....maybe little pieces of the spider gears inside? ... are you sure its not a front wheel bearing and the noise is traveling and sounding like the rear end?
With it sitting still see how much "play" you have back and forth in the driveshaft.


1937 Chevy Pickup
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1952 Chevy Panel
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1950 Chevy Coupe
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I'd rather walk and carry a Chevy hub cap than ride in a Ferd.
I can explain it to you, but I can't understand it for you smile