If I remember right They are mushroomed on both ends. I drilled mine very carefully. The rear one on the pinion came out fairly easy, but the front on the driveshaft was stuck in a bind, I think because the splines on the driveshaft were really worn out. Edit, after seeing seb fontana' s post I do remember using a drift punch on the pinion, but the driveshaft side I had to drill out.
Dan that explain why I can't get them to move any further. The rear is the only one I need to get loose. I will put my surgeon hands on and see what I can do.
It is peened into a chamfered hole... Center punch it and drill 1/8" down or so to remove the head off , then you should be able to punch it out , unless someone welded the end