I got tired of leaking oil when removing the engine and transmission together. When my son bought his 2000 Evolution Orange Miata, the previous owner had replaced the drive shaft. It was included in the sale. We knew when we saw it that we could use the transmission end for a tool to plug the rear of transmissions when we were removing them.
I used a cut-off tool and cut the U-joint at the cups. Then punched out the cups. I did not understand why you cannot rebuild these joints until I had removed the parts. It is clear the cups will not come out the ends of the yoke due to the method used to keep them in place.
I left the yoke holes so we can use a bungee cord to secure the tool to the transmission.