Tractor Repair: 574 International, pto drive shaft, input shaft

Question
Hi, my tractor is a 574 International diesel.It is leaking hydraulic/transmision oil.It travels down the output shaft and ends up all over the clutch.I split the tractor and changed two oil seals on the input shaft.It still leaks!The splines on the input shaft where it goes into the clutch are wore probablly35% Could that be part of my problem? Or are there more seals in farther that i did not see? Thank you! Looking forward to hearing from you.

Answer
  There is an inner seal inside the pto drive shaft and an outer seal inside the throw out bearing carrier, and an o-ring around the outside of the carrier.  The worn splines would not be part of the problem, but a worn bearing could allow the shafts to move side to side which could allow oil to leak past the seal.  The seals also have to be installed correctly.  If the inner seal in the pto drive shaft is not installed to the correct depth or is installed backwards, it will leak.