Bill, first the oil leak is probably coming from your front(rear
main)flywheel oil seal.There is no oil in the clutch housing.Is it gear
oil(rather smelly)? or engine oil?If it is gear oil it might be coming from
the front shaft oil seal inside the tranny that drives the clutch.In this
case the clutch will not last long as oil will get on the facings which may
also eventually happen with the front main oil seal.The bellhousing crack can
be rewelded once you remove the transmission and separate the bellhousing
from the tranny....but are you sure it is cracked or is it casting
flashing?In any event removal of the gaersbox is in order.

Ed Berroth
84 Westy Wolf
87 Stinkcrow
88 735i
84F250