I didn't see this thread til now. In my build thread, my install shows I broke the Snap ring pulling the Spud shaft for my Rubicrawler install. Glad you got it done though. I'm a tech for a living with a little bit of transmission experience and shop access. And it still took me 4-5HRS to install the Crawler. I did do my SYE at the same time, but I'm not counting that part. It is an involved install.
I was using a high end 1/2" cordless gun and a snap-on puller cross bar. It started to become difficult to pull, as I had been forwarned. So I stopped for a second and then gave it the full onion of power from the gun and pulled the spud shaft over the snap ring through the splines.