You might be able to find some of my older threads if you do some searching, I too have had some problems. In fact mine were so bad I had thought about calling my Titan The USS Valdez
Please keep in mind though, my problems were very bad mostly because of a poor quality service organization.
#1- Rear diff leaking, solved with new pinion seal
#2- Tranny/transfer case leaking, got better by proper torqueing one of the bolts that holds transfer case to the tranny
#3- Tranny/transfer case still leaking, got better by changing the crushring on the drain plug.
#4- Tranny/transfer case still leaking, finally solved by proper torqueing the other bolt that holds transfer case to the tranny because it would have been too logical to check the torque on both bolts at the same time.
Some people have also reported tranny leaks as a result of the cooling line into the tranny from the cooler, the hose connection was not tight, as I recall.
Good luck, and don't give up the faith, I love my Titan now, but i had a rough go of it for a while, but like I said, I really believe my simple little problem was made worse by a bad service organization.