to be safe, I would get a larger tranny cooler as well if all you have is the stock trailer package cooler

 

Tell me more!!

 

Stock Trans cooler is fine .......trans gets hot when truck not geared right and you are in and out of lockup alot ............ and or constantly downshifting / upshifting I tow 7000lb enclosed on 1000 mile trips trans rarely gets over 185.runs 170 most of the time

 

I think you should see if you can find someone with a compatable trailer, or really weigh yours down and see how it feels, I did something like you and ended up almost killing my truck, I wouldnt recommend it