Damn that sucks. I hate to say it but I think you are going to have to consult with a transmission shop. Without being able to see your transmission, its hard to pin point the problem because there are various causes. First and foremost, the case bushing could be bad. The case bushing is in the very back of the case, not the tailshaft housing but the case. The tailshaft housing bushing could be worn out causing it to wear out the case bushing. The case could be worn out were the steel stem of the governor rides. There is a steel slug that helps line up the governor by fitting inside the top of the governor gear. It could also be the half bubble cover that covers the governor. It helps manage runout of the governor. If it is dented too far in, the governor can be tight. If it is bubbled out more than it should be, the rotation of the output shaft will try to spit it out. I hope this helps. Like i said, it might be time to consult a shop. Good luck man.