Putting hitch and wiring on my 04 Durango. I think it may have had a tow package, some cut wires on the frame in back. If it had a tow package, would it have come with a tranny oil cooler, and where would it be? and how hard is it to put one on? or do I really need it. My D is rated 9500 lbs. max, the trailer I am getting is only 6500 max. The RV dealer said I would not need it. I do not beleive him, and would rather be safe than sorry later... Any help would be greatly appreciated...