Clutch Disc Direction

Shop Notes:
The splined area of the clutch disc sticks out further on one side of the disc than the other. The side that sticks out further goes to the back of the tractor. The flatter side goes to the flywheel.

What happens if you get it in backwards? The clutch will not release when you press on the clutch. 

Why? because the tall side of the clutch will hit the nut on the crankshaft and prevent the disc from going flat against the pressure plate.