Here is the fix and it can be done with the engine in the vehicle, most of the time. Drill a series of holes the distance of the crack, tap the holes with machine thread and install machine screws. These holes you dill need to be almost touching each other. Then with all the screws in place grind off the heads and weld them together. I have seen an old machinest do this 3 times, it worked all 3 times.
