looks like diesel

[RussP]

Your oil and tranny coolers are raw water cooled and one of them may be leaking. Some Cummins also have raw water after coolers which could cause problems.

RussP

[In Memory Walter K]

Check your tranny fluid. Low? Cloudy? The oil coolers are an easy replacement if your problem is them. Both going at the same time seems unlikely. You just changed your filters. spill or leak any oil into your bilge?
If you didn't have this problem before the filter change, I'd suspect something happened there. Check your engine oil. Low? Cloudy? Walter

[kellysmall]

I had a similar thing happen on my gassers in the B25. The engine oil and transmission coolers are integral in the same shell. I noticed one engine was putting out a sheen in the exhaust water, and then I noticed a drop in transmission fluid on that engine's gears. A few months later, the same sheen appeared on the other side. This time, it was the engine oil level that was dropping. Two new Lenco coolers later, the problem was solved.

-Kel

[34Hatt]

Does your 270 have Fuel cooler??

If so make sure you don't have water in fuel also could be leaking there and mixing.