One other possibility of leak in that area would be the back end of the oil pan gasket. That could be replaced without splitting. The rear crankshaft seal or transmission shaft seal would require splitting. Can you tell if it is engine oil or transmission oil? Can be hard to tell since clutch housing is full of clutch dust that mixes with hydraulic oil and makes it black like engine oil. If powershift, crank seal or transmission seal can be fixed with one split. A synchro range could require two splits if both seals are leaking. If you have that much oil in there, chances are good that you will need a new clutch. One split and seals only will likely cost in the $1000.00 range at a dealer. If clutch is needed or second split, cost will be considerably higher.
Another thing just occurred to me. It is possible that oil from the leak you had at oil line could have entered the clutch housing. There is a rubber boot under dash where clutch linkage passes through. Chances are good with the age of the tractor, that the boot migh be damaged or missing and oil could have entered there.
Another thing just occurred to me. It is possible that oil from the leak you had at oil line could have entered the clutch housing. There is a rubber boot under dash where clutch linkage passes through. Chances are good with the age of the tractor, that the boot migh be damaged or missing and oil could have entered there.