Man I am always full of ignorant questions because I read about, ask questions about whatever I need to know on my Mopar. , so now I will ask ya'll, Mopar lovers who I know will give me the best answer.

Many people have replaced a yoke seal by simply stamping nut position and returning to same.

The problem with replacing the entire yoke, with the above method is that the point of reference is lost.....you're screwed.

Thanks for the answers guys, it really helped me understand that was not what I wanted to hear, but needed to hear. I am not capable of doing that job personally but could probably find someone who will not rob me to badly to get it done.
The reason that I am wanting to change the pinion yoke is that I installed a 727 and slip yoke needs to be changed to the bigger one that fits, and I thought that if I didn't use the same size u-joints throughout the shaft that I would have a weak spot, even with a cross u-joint at the pinion. I do have decent traction so I wanted to try to do it right without tearing into the third member. So who makes good strong cross joints?

If you want to get really technical...

The yoke can be changed but you need to measure the turning torque of the axle (drums off!) and write that number down. Then change the yoke, tighten the pinion nut untill you match the measured turning torque AND reach minimum torque spec on the pinion nut. If you reach turning torque before tightening torque your stuck though, it must come apart for a new crush sleeve (the old one has collapsed too far)

There's lots of extra friction when spinning the diff and shafts so you need accurate and repatable torque wrench for rotating torque.

Due to the gotchas in this process,I don't reccomend it.

You know I hate making it sound like a big deal about a crush sleeve, but I do not have a clue on this, as you are aware of. Can it be changed from behind the pinion yoke or does the ring and pinion have to come out and go in that way? I can't seem to find a breakdown diagram on this. Thanks again.

that's crezy

If you do replace the crush sleeve be aware that they sometimes take a disturbing amount of torque to begin crushing. Once they begin moving it gets much easier to do.

The last one I did was ugly. Pneumatics wouldn't touch it. I'm sure you could have done it with an industrial 3/4" drive but I don't have one.
The torque required was bending my steel table. I had to put a jack under the table mounted vise, clamp the yoke in the vise, put a 4' long black pipe over the ratchet handle, and test the lifetime warranty on the tools. I had been pulling hard on the pipe with no results. Then, I cleared the floor behind me (landing zone if something broke and I went flying) and laid into it HARD. It went but wasn't happy about it.

https://www.youtube.com/watch?v=8T8ZG5DKsi0