Help with oil leak

[N3BP]

Hey Guys,

79 B7100 has an oil leak on the back right hand side of the block somewhere. Had a small puddle on the garage floor. See attached pics. Replaced rear main this summer and it's not leaking out the plug in the bellhousing, so that's ok. Thought it was an oil pan gasket, so I just replaced that. Appears to be wet behind the frame mount and to the back of the block. I didn't remember seeing anything obvious when I had the frame off.

I was hoping for some ideals or suggestions before I go tearing it apart again!

Thanks!

 

[North Idaho Wolfman]

On the back of the block but on the left hand side there is a oil galley plug that has been know to fail and cause oil to leak across the back of the engine, also check that the valve cover isn't leaking.