1968 Dart sudden rear end noise.

1968 Dart 270 said

Yes,7 1/4" rear with 273 v8. Would the pin be the piece that was making a sound like a marble bouncing around in the rear end? Thankfully I got it to the garage before it did grenade. Can you tell me how to fix it? What causes the pin to come loose? I have never abused this car at all since I've owned it. When it started doing this I was driving about 35 mph on a city street. I hope it can be fixed easily and nothing was damaged yet.

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First off a 7 1/4" rear end is a very light duty rear end.

As the small 2 spider gears start to wear, it wrenches on the cross pin in the case. So much so that it eggs out the case that the cross pin sits in.
Eventually it sheers the the 3/16" bolt pin on the end and the cross pin starts to work out.

They used to sell diff rebuild kits on rock auto for the later year a bodies. New pin, spider gears, side gears, shim washers and anchor pin/bolt.

In reality not much fixing them when the diff case wears out from the cross pin moving.

Last ditch hillbilly effort > weld the cross pin into the case and start looking for an 8 3/4 as a replacement.

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