Jack,
Once you get the tractor back you can work the heck out of it but when the wheels dig and bounce up and down you will break it the next time. I have built a few kioti front diffs and it is not a pretty site when the blow apart. Work it hard but try not to bounce it because these front axles don't like it.
The front drive shaft does not have a shear pin, just two splice couplers on each end. As you noticed the diff will go before anything else. Good luck