Did they weld the open diff close to lock it? Or just weld the gears on the end of the axles?
Well, especially if you've already gotten one side out, then you have a good sense of what is preventing you from pulling the other side out: that weld is acting as a fat ring that's preventing that axle from sliding out of there. By whatever means you have to get that weld cut down so that it's no longer has the ring and the axle shaft joined together, and it's no longer too fat to slide out through the hole in that gear.Open to any ideas. Only have a mig though.