This is what happened on my way to parade. Does anyone know if this kind of damage can be welded?

 

It can be. However the issue would be if whatever caused the crack may have also distorted the bearing and seal mating surfaces beneath. I have a spare diff if you need one. Just PM me.

 

It can be welded no problem by someone who knows what they are doing. Pre-heat and not putting too much heat into a small area of the part as its being welded is key here so as to not warp the seal/bearing bore.

As for the bearing and seal surfaces, a quick check with a dial bore gauge or telescoping gauge and mic would tell that story. Worst case is weld buildup and re-machine.

I have done similar type repairs on other equipment in the past. If you take it to a machine shop (not just a welder) you should be ok.