For the first time this year I plugged my block heater since it was going down to about zero. This morning I woke up to a puddle of tranny fluid that appeared to have come from one of the tranny lines that are rubber/steel and it is leaking where the rubber and steel meet. Could this have anything to do with the block heater or is it coincidence? Truck is just out of warranty and they have already replaced the rear seal on engine. Any comments/suggestions would be greatly appreciated. Thanks

The block heater should not have anything to do with the transmission lines as far as I know, but my truck is a 2005. I did have a coolant leak at the torqueconverter cooler (looks like a small radiator mounted near the firewall near the front of the transmission.) The coolant looks almost like trans fluid so make sure the leak is not coolant.

I did a quick search on Turbo Diesel registry web suite and did not see anything specific on the trans lines leaking, but several posts on the coolant leak going to the cooler? You might also try posting here:
http://www.cumminsforum.com/forum/index.php