Mine did have a rear main leak as well as the O ring from the injector harness. The rear main caused the the front of the bell housing to become wet. Once that was straight, the dealer figured out that the O ring on the injector harness was leaking on the right bank because the block was wet on the right side all the way down to the tranny. It just wasnt as wet as it was when the rear main leak was also present.
You should be under warranty (I am assuming your truck is an '06 by your screen name) unless you are over 100,000. if under warranty take it to the dealer.