Mazda 6 Towing Help!

I am currently trying to tow a U-haul trailer down to Florida from Wisconsin. The trailer is 5 X 8 and weighs 900 lbs. I am hoping to put about 700 lbs of stuff in it, which would result in about 1600 lbs of stuff being towed. Will my Mazda 6 (V6) be okay towing this all the way down to Florida without buying a transimission cooling system. U-Haul was trying to convince me that I needed one for $160. Is there anything inexpensive I can do to make this easier on my car? Thanks for the help.

The Mazda 6 manual says that the car can not tow anything let alone 1600 Ibs