Ok, So, I've searched the threads on here a few times looking for a definative answer to this problem. so far come up with that if it isn't the parking brake ceasing. (Which we've looked at and it isn't in this case.) you pretty much bring your truck back to ford and get your money back?? haha. but seriously now... This is my uncle's brand new 2008 4X2. and around 100km an hour the thing starts shakin' like crazy... but only when towing his car trailer. He's had many Fords before and he's in the car restoration business so towing isn't "new" to him (trailer loaded properly/ tire pressure, etc.)...so, its something with the truck.... anyways, I've suggested this site to him first off. Before the guess and check game starts with the dealership... so anyone who's had this problem and actually "solved" it, we'd be grateful for your help or any suggestions here. thanks in advance. Hotspurs04FX4

 

Look at things like the trailer tires are out of balance. The frames on the trucks are very stiff and have a tendency to transmit vibrations into the vehicle that normally would not be felt. Especially since it only occurs while towing. The common denominator here is the trailer.
Does he pull any other trailers and it does or does not occur with them.

 

I have 2 different trailers I tow one has bad tires and causes a vibration in the sterring whell , the other makes the truck drive better under load less bounce.

 

Does it do it with the trailer loaded, unloaded, or both? How much does the rig weigh, and are you using a load equalizing hitch?