That is not the right drive. It is for a newer model. To remove the drive, tap the retainer back off the snap ring. There is a tool for removing the snap ring but a pair of channel locks & foul language will get it off. Then you can remove the retainer & drive. Sometimes there is a ridge where the snap ring was that you will have to file down. Check the rear plate on the armature. If there is no looseness you will not need to replace it. I drill a hole in the back of the bushing & drive it out with something sharp. Some guys run a tap down in it till it forces it out. You can go over the commutater with some fine emery cloth. It will be OK.
