Take the splash shield out and throw it away. It's purpose was to prevent oil from getting on the pto shaft and walking up to the clutch since those tractors had the pto shaft running parallel to the ground. It did it's job well, it also prevented oil from making it's way to the idler bearings. Use a input shaft nut with a seal in it, and use permatex "right stuff" on the threads and the groove in the threads to prevent the potentially leaky input shaft o-ring (that cannot be replaced very easily without pulling the input shaft) from pushing oil to the clutch, since your newly installed seal will prevent that leaking oil from running back into the transmission.
Your pto shaft may or may not have the matching seal surface machined into it for your new seal.