That would leave oil behind the flywheel.  If there is none, then it is nothing at the very back of the engine.



Lawrenceville, GA

...And the rear block plug for the camshaft..


Paul

That's correct.  If there is no oil at all inside the bellhousing on the back of the engine then it is not the rear main.

Things that the rear main takes blame for include but are not limited to the oil pan, oil pump, oil filter, valve covers, valley cover.



Lawrenceville, GA

I assume while checking for oil leaks if you pull the clutch cover and do not see any oil leaking behind the flywheel/crank end, you do not have a rear main oil leak.