Thank you nibkb2 and billr, I know cast is not the best material to put stress on, but I did make sure I only used hand tools, no air tools. I also kept the cast cap to the back of the axle beam and my face to the front. I did use some light weight oil on the threads. Just as a note, I also have a tie rod end puller that is cast I believe (attachment) and that has a lot of stress placed on it. Again only hand tools are used with it.
Well, Thanks all that replied. nickb2, billr. , and all others.
The bottom line is nickb2 has made a strong point of safety first.
When using an impact gun you need to only use impact approved tools, sockets, chisels, etc
I don't use an impact gun too often (except my 8 lug wheels) but I have impact approved sockets, etc when I do.
In my case using hand tools I can still see the possible safety hazard of the cast cup shattering, especially if it had a flaw in the casting.
So take nickb2's safety warning to heart and lets all Thank him for his concern.