I have been trying to diagnose a slow oil leak originating somewhere between where the transmission/bellhousing (g56) mounts to the block. It has been accumulating at the back lip of the oil pan, not enough to drip on the ground, but enough that i can clean it all off and it comes back in a few hundred miles. I checked the bolts and the pan and they seemed plenty tight.

So my question is, does it sound like a rear main seal and why would it go so early? (truck has 48k). Looks like the flywheel could have some oil on it and i'm wondering if it poses a threat of getting oil in the clutch? Talked to the dealer and they said if it is not leaking really bad it is hard to get it fixed under warranty, same with my CP3 that leaks when it is cold. I guess if they drop the tranny and tear it apart and "decide" that it is not a bad seal than i get the bill.
Should i just wait until i finish of my clutch and then replace it with South Bend DD, loose the DMF, and repalce the camshaft/rear main while im in there?

 

just to be clear, is there any chance it's coming from where the tail shaft mounts to the transfer case, and running down?

 

My 07 5.9 has the exact same thing.... I noticed it about 14,000 miles and it now has 23,000 on it. It will get a little " Wet" around the back of the pan, same place you describe. Every oil change I just clean it off. Mine never drips but one time there was a drip hanging on a bolt but went away. I had dealer look and they said it is normal " Sweating" of the gasket. They will not fix under warranty unless it leaves a puddle, so I am just watching it. I posted a picture of my drip and from all the responses I got, they said to leave it alone

 

you know diesels are like old Harleys. They leave a scent trail. Generally a normal seep will not contiminate a clutch.

 

https://www.dieseltruckresource.com/...d.php?t=187857

There is the link to my thread on the same issue your having. See the picture I included and see if it's similar.

 

You can normally trace the wetness back to the front. Either a mix of fuel leaking from the CP3 with oil and dirt, or the CP3 access plug on the front of the motor was put on without a seal. A motor with high compression plus a turbocharger is going to have a lot of blow-by. The tube for this drops on the left side of the motor right at the rail level. That is usually the root of mine. I did my clutch not to long ago and was prepared to do the rear main. When I dropped the flywheel down, there was not a smear or sign of any wetness around it. The seal was dry, as well as the clutch area. Bell housing had dust and residual clutch material mixed with a little grease from initial assembly. Just get a good brake cleaner that dries almost instantly and do it every oil change.

Chris

 

I've got it too, and I believe it to be blow by from the breather tube while driving.

 

Thanks guys, good to know i'm not the only one. I cleaned off the back of the pan/bell housing w/ some break cleaner and did a couple hundred mile this wkend, just checked it and it looked dry. Guess i won't worry unless i see it dripping all over the driveway. The CP3 weeping is a little more anoying, i found a wiring harness right under CP3 that was soaked in diesel and the electric tape is all melted and sticky, wonder if those wires could short? I can't ever see enough fuel leaking to determine where its coming from, probably can't get that fixed under warranty either unitil it drips all over the ground.