has anyone else had an atf fluid drip right behind the front tow hook on the rubber line that runs up to the ATF cooler??  

Hey bro, I have had several customers with the exact symptom and had it on my 2006 truck. The crimp on some of the fittings on the trans cooler lines (only on the 2006 and later trucks with the larger lines on the 6 spd Allison) are not completely crushed. There is really no other feasible method of repair, besides replacing the line yourself or having it replaced under warranty if possible. I have replaced atleast 3 sets of them so far. All on 2006 trucks. No 1 line in particular has the problem specifically, it seems any of the 3 lines: going from trans to the radiator, radiator to the cooler and/or return to trans could leak at the fittings. Just make sure you check your trans level meanwhile. Dont let it fall below the add mark.  

that sounds like the problem i have. i am gonna see if i can get it under warranty the truck only has 52000 miles on it. its not a bad leak, just a slow constant one.  

Same leak.  Number 1 line at the crimp. '06 LBZ with 57K on it.  Dealer said it wasn't covered.  I assumed it wasn't. Replaced it yesterday.  It was a bear to swap.  Not much room.  Would've helped a lot to have someone working from the top and someone else working from the bottom.  I pulled the grill, the air box, and disconnected the top side of the boosted air intake. Still was a pain.  
 Still love this truck.  Only other problem I've had with it was a rear hub leak.  My last truck was an '02 duramax and I had tons of problems with it.  Was towed about 4 times.  Maybe I'm speaking too soon.  Most of those problems started at 70K.