Possible rear main seal leak?
 

First of this is a great site and I have been lurking and learning alot here for the last 2 months. That out of the way and on to my problem. Last thursday I changed the oil and fuel filter and greased the zerk fittings and cleaned the oil pan up. All was good. Then Friday I drove her 400 miles to Virginia. When I got there I noticed oil coming out of the adapter plate between the motor and the bellhousing that blew back onto the trans. Took her into the dealer today and they cleaned up the oil and added die to the oil to check it. They then supposedly drove it 30 miles ( funny thing the odometer didnt even move 10 miles) and said no leak found. The machanic said that they use alot of assembly lube on these things when they are assembled and that is what oozed out. The truck has 4100 miles on her now. Does this seem right to anyone? I have rebuilt my fair share of gassers and never heard of assembly lube leaking out of the thing. The amount of oil was a minor amount but I dont think this is normal. It all happened on that trip only and this isnt the trucks first road trip as I bought it in Texas and drove her back to South Carolina. Am I being paranoid? Any thoughts are welcome.

mine is leaking also same thing they found no problem. if they did do the dye test then it will show up under uv light. good luck and keep us posted

It wasn't assy lube. Isn't it funny what comes out of some techs mouths to deflect an honest question? I thought Cummins runs in new engines pretty good before crating and shipping them. Any lube would show up then and be wiped off.

What kind of oil did you use? Did you use 3 gallons?

In any event, I'd just keep an eye on it for now. If there is a follow on problem, its been documented at a dealer.

I had the same thing when mine was new and it was a substance that they coat some new parts with...I think it is called "cosmolene". I did not buy this at first either..... but after another 1000 or so miles it did go away.

I put in 3 gallons of delvac 1300 in her and used fleet gaurd filters. I will probably switch to the premium blue oil next time though. I guess that I will keep an eye on it. I am just a little worried about the price of these motors once the warrenty runs out. Not to mention that I am in the military and hoping to go over seas in 2 years. I hate the thought of trying to find a Cummins dealer in Iceland. Filters is one thing but hard parts are another. I am just trying to take care of her so she will last and be more than willing when I ask her to. Thanks guys.