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Differential Case Small Crack

Old Feb 21, 2009 | 10:50 PM
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Default Differential Case Small Crack

I noticed a small crack in my differential case (assembly which ring gear mounts to). It is about 1/4 inch and extends from the corner of the window on ring gear side. I could not get a good photo to show. This appears NOT to be all the way through the case. I could not see it from the inside. My queation is, Is this usable? I've read inspection instructins which say to look for cracks from window to pin hole. This is no where near that bad but still I'm concerned. Any comments are appreciated.
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Old Feb 21, 2009 | 11:56 PM
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If it is indeed a crack, then I would replace it regardless for peace of mind. But before you replace it, I would ask tracdogg2 or GTR1999 for their opinions on it - they are the differential gurus here.
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Old Feb 22, 2009 | 09:41 AM
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If there is a crack in it, then it's NG. Toss it and get a good used one or a new bare case. Don't waste your money on a new Loaded Eaton.
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Old Feb 22, 2009 | 10:00 AM
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thanks again. Do most used units have cracks?
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Old Feb 22, 2009 | 01:29 PM
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Hi

Of course not.

Check your crack with the die check method. This is a red colored spray that contains a special creeping oil which intrudes the crack. Then this is washed off and then sprayed with kind of a white powder. The crack then shows up after a while because the residual red oil will wetten the powder. This proofs your crack if it is one.
If it only shows on one side, you might want to polish it before crack check with fine sandpaper. This just to assure your not checking a scratch only.

Of course, other crack check methods also work, like eddy current inspections etc, but this requires special equipment.

The die check spray should be readily available.

Good luck. Günther
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Old Feb 22, 2009 | 02:42 PM
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The Dye Gunther mentions would work but I use brake cleaner and compressed air. The crack will stay wet after the surface is dried with the air.
There should be no cracks, I'd say 50% of the early eatons I get in to blueprint are cracked. These were from 65-68 in 69 -79 the design changed, they crack too but not nearly as much.
If you look up my threads on diff's I show all this stuff so you know what to look for and what your options are.
Good luck if you need any help let me know.
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Old Feb 22, 2009 | 06:56 PM
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Mine had a early eaton also like gary said.. i found that it had cracked also.. same place as usual. who knows when, i might have happened many owners ago...I found out when i tried to trade in my old rear end for a rebuilt one..

many of them are cracked and probably just as many are out there cracked and the owner does not even know...

just don't sidestep your clutch at 5000 rpm and it may last forever...
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Old Feb 23, 2009 | 05:10 AM
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Hi

If you have a confirmed crack, you can impossibly keep on driving with it.

The difference here is that you know it is cracked, regardless if this is possibly normal etc. Once you know, that's it.

A crack check ( dye or whatever ) can be done with the cage installed.

Rgds. Günther
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Old Feb 25, 2009 | 09:14 PM
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Thanks for the replies, I'm going with a different assembly.
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