I dont know if the tranny is different for the 4.7's but for my hemi, it's really important to use the tow haul. a downshift under power into 2 prime or whatever it's called can grenade your tranny in a hurry.

 

for the rear of the enclosed trailers
when towing
consider "airtabs"
or make your own 'Wheeler Vortex Generators'
from any round piece of metal or plastic

http://www.airtab.com/





or for DIY experiments:



the diameter does not have to be exactly 4 and 15/32
it can be any diameter from about 2.5 inches to 6 inches

in addition to a modest MPG improvement
these devices reduce the sway of trailers
especially when larger vehicles pass at high speeds