Some background:
I have a 2016 XLT , 3.5 engine with 4WD/AWD
It came without the towing package and, looking at retro-fitting the factory one, i spent quite some time researching the subject
Numerous post and threads on this forum warn that you can only get a 2000lbs tow rating instead of the 5000lbs if the package was not installed by the factory
Obviously, I you could get ALL the parts included in the towing package, this warning make no sense whatsoever ( I m not talking liability but rather mechanical and physical performances)
The BIG issue raised is that the transmission used on the towing package is not the same on non 3,5 turbo trucks
Basically the 6F55 is used instead of the 6F50
I read some comments that the highest rated 6F55 is used because the extra load created by towing,,,, that is 100% BS and completely backward
Transmission are rated by the amount of torque and horsepower FROM the engine that they can handle
An engine putting out 300lbs is putting out 300lbs, REGARDLESS of the load towed, being nothing, 2000lbs or 5000lbs
There is no different part # on the tranny (6F50) used by my truck if equipped with towing package or not
Part # is DA8Z-7000-D
And don't tell me this non-sense that you can have different parts with the same part #
Also, the radiator used on my truck is exactly the same with or without the oil cooler/towing package
Part #FB5Z-80005-A.
As a matter of fact, that part translate to a Motorcraft part # (RAD119) that specifically state that is is also for the oil cooler option
Anyhow, as long that you use all the factory parts, the end result is no different that what the factory did
obviously, the above only apply to my truck since i have not researched other years/models