You have to remove all of them on top. There are no external bolts that hold internals in place per se. Internals become loose when you split the cases. Flip the motor upside down and remove all the bolts except the one that holds the large round plug in place. You do not have to remove the oil pan. Remove the bottom case. The transmission counter shaft, shift forks, oil pump, etc. remain in the bottom case.
Best idea is to get a shop manual if you don't have one.
