QUOTE(dangrouche @ Dec 7 2009, 09:11 AM)
you have to smell the oil; tranny oil is stronger and stinky smell when compared to motor oil. tranny oil is also thicker than SAE20-50 or SAE30. touch a drop between two fingers and sniff. The only seal back there for the tranny is the input shaft, which I believe is higher than the input shaft seal and hard to remove unless the input shaft is removed (tranny apart). i have never had a leaky input shaft seal. your likely candidate would be your flywheel crankshaft seal, about 3 inches in diameter. you will need to change the O ring , the felt washer as well when you are in there. these are the bare minimium items to change when the tranny and motor is undocked. go to the pelican board for technical writeup for a clutch change.
the 901 seal is easy to remove the early 72 73 915 is the one where the shaft has to be removed!