Post a picture of the broken piece if you can.
If it is broke off at the smooth pin part then you could possibly pull it out with a small magnet.
If it is broke at the threaded part then you will have to unscrew what remains.
I was able to use a right angle drill attachment to drill into...
https://forum.ih8mud.com/threads/differential-shaft-pin-broken.641837/
I used the broken piece. Drilled a hole in it and used it as a guide to drill into what was left of the pin. Then used an easy out type extractor to back the broken piece out.
I've had to do this twice on two different 1974...