I have a 2011 Ecoboost Max trail package and tow a 7,000 pound trailer. While that is not a real heavy trailer. I have towed it out of Hill City South Dakota and from Nebraska to Idaho over the highest mountain on I-80 at Laramie, Wyo also coming down Wahsatch. It handles quite well. You have an option with the trans which to lock out a gear or when you brake coming down a hill "in tow mode" the trans automatically shifts down a gear until you push the accelerator again. Its about the trans not the engine. Ford planned for it to tow. Uphill for the motor and downhill for the trans. Cap that off with a correct gain of 6 on the trailer brakes and never an issue