Take the gear shift handle out and see if the slots in the shift rails all line up in neutral. Take the little inspection plate off the bottom of the center section (4 -1/4 inch cap screws) and look in there with a light. This is the hole you go through to adjust the PTO clutch. Try to have someone engage the PTO clutch while you look and see what the clutch linkage does. On the main clutch, do you have too much free travel/ With the clutch petal down and engine running does the clutch make any noise/