I agree with Aviator41's suggestion above. The grease I use is called dielectric grease, but it is likely the same stuff. Years ago when we purchased our first travel trailer, the service manager told me that if I used it faithfully and liberally, that I wouldn't have any pigtail connector issues. He was correct. I swear by the stuff.
There's no doubt the new F350's are nice and powerful but I will hang onto my bullet proof 7.3 as long as I can. Wait until you have to throw a new radiator into your tuck at 40K miles.
My 2011 F-250 split it's rad at 41000 miles. I left the dealership $2000 poorer. When I asked the service writer how common this issue was, his reply was, "A lot more common than Ford would ever admit." His theory was that the frame flexing was contributing to the separation of the core and bottom plastic tank. The leak is almost always at the drivers lower side.