Here is what the inside of the differential looks like in a tractor without the locking differential. Looks pretty clean too.
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I took the U bolts off that hold the rear to the frame, 2 of the 4 bolts on the front support and loosened the other 2 on the front support. I then put a strap across the top to support some of the weight and it gave me enough clearence to remove the axle cover plate.
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Here is side that the seal failed on. I'm not sure if water got in it and caused it to fail but the other side that is not leaking is clean.