Plus one on the idea of driving a wooden stake into the pins to get them out.
My 5th and reverse pins were really stuck. (That's why I was replacing them). I tried using a tap and then a screw extractor, but they couldn't bite into the hardened pins. I tried various pick tools, but the little hole in the end was too small. Then I tried the dowel and it did the trick. Actually, my peg was square, but I just drove it into the pin and wiggled it out.
It was not much fun to get the 5th and reverse sleeves out, but a small screwdriver driven along the seam did the trick. Unfortunately, the last two taps of the reverse sleeve sent it into the transmission, greatly complicating things. It was stopped by the selector shaft, but was still too big to fit out of the hole and was too far in to use any tools to crush it. It took several hours to finally get it out. Some days are like that.
Amazingly, my 1-4 shift pins had been done, but the 5th and reverse had not, making it difficult to shift from 3rd to 4th without going to 5th instead. I just can't follow the logic path that says to remove the transmission from the car and then only service some of the pins.