This is an example of a case repair. A new case would be about $1500, so we brazed a steel denture into the broken area. The strength of a good brazed repair with cast iron is as strong if not stronger than the original case. Bronze welding is a very forgiving, strong repair and used extensively when repairing cast iron. We prefer brazing cast over welding in most instances. Many race cars use tubular steel frames with brazed joints. In this particular instance, the case performed beautifully, standing up to several years of use with no issues before the tractor was sold. 

Goldoni Base 20 Rear Diff Case Repair

Broken case repair using a "denture" and bronze. Italian Tractors of North America.