Frankie no matter how the words are packaged, it's an a$$ packing which STARTS the crack or breaks the diff. How many diff's. from street cars/never on a track have you found with hairline cracks or fractures?
The Wheeler's, Drago's and others who view lots of diff's. from never tracked diff's. to race tracked diff's. know the facts.
It would appear one fact (Jim's prepped diff. housing) is only the passenger side breaks. Question, why does only the passenger side have OEM notches and or get beefed up? Diff. pinion rotational direction/speed?