I have the clips off, and I’ve tried a c-clamp and some sockets; I wasn’t able to apply enough force normally, so I tried putting the c-clamp handle in a vise, and then I spun the clamp and prop shaft as one. I certainly had enough leverage, but the u joint was not budging, and the clamp was starting to flex!

I know a lot of people use a vise, but mine is not large enough for the yolk + both sockets…

Are there any other methods for trying to get these out?