N14 oil leak

At first glance I was going to say rear main but looking closer that is rear pan leaking down then across over to the flywheel hole. While pan is off might be time for rod and main brgs depending on milage. It is very doubtfull its rear main leaking between block and the engine bell.

 

Oil can leak and follow seams and track to weird places. The leak might be from somewhere else all together. I also do not think it is the rear main.

 

Try to snug up those pan bolts. The pan gasket is just a paper type and eventually leaks.

 

To test for a rear main seal take it to a preasure washer and remove the plug from the bottom of the bellhousing, run the engine at about 1200 RPM, with it warm is best, put the nozzle end partially in the hole you took the plug out of, with a soapy spray, be sure the cover plate is on that will clean out the bell housing. Spray in for at least a minute, then let it drain and do it again at least three times. Then take the truck and leave it run for at least ten minutes, shut it down if the oil comes out the plug hole it is inside the housing or the seal. if not you can see if it is running outside the housing or the oil pan.
I torque oil pan bolts to 55 and the little ones to 25 ft lbs

 

just did a rear main seal on a n-14...did not fix the leak.
there is a cam casting plug/freeze plug in the rear stucture that was the problem