i think a 3.9 is going to really struggle with a trailer this heavy. Your chassis will haul it, your motor will not. If your going to attempt it yes you should use a weight distributing hitch. My toy hauler weighs 4500 pounds empty and my buddy with a 2002 chevy 1500 4.2l cant haul it up a hill. The chevy wont out pull my 5.2l dakota (despite being "full size") but it will out haul a 3.9l, my other friend has one of those and he struggles with a tent trailer up hills.

 

How far you hauling this trailer? and over what kind of terrain?

 

The 600 mile drive home was flawless and I was instantly in love with the truck. I've already removed the tonneau cover and am considering whether or not to keep the running boards.

 

Should be a pic here showing my 04 Reg Cab V8 5sp 4wd Dak.
15 mpg towing 3500lbs w 700 tongue wt. 21mpg empty hwy.
Love this Truck !!