Truck in signature. Bought it nearly a year old sitting on the lot with 400 miles. Of course on the test drive I didn't notice anything, but within the first few weeks I noticed a vibe around 67 mph. at 1,000 miles took to dealership and they replaced 3 tires. Slight improvement at first, but then got worse as more miles added on. at 2,800 miles took to dealership again, this time 4 new tires. Helped marginally for the first few hundred miles again, but returned.

Now it gets interesting. By chance I pulled my trailer on the highway and at 62 mph+ with trailer the vibe is VERY bad. Like borderline uncontrollable. I pull a trailer regularly, but not as much at highway speed so I didn't notice until recently. So this last weekend I switched trailers with my buddy to be confident the trailer was not the problem and it isn't. Going back to dealer with trailer on wednesday so service manager can ride along.

Anyone else with insight? and yes I've read the other vibration threads, but nothing mentioned in any of them about towing.

 

Driveshaft

 

Service manager says "yup it vibrates" Oh gee really I drove all the way out here with a trailer because it was perfectly fine. Then they send me packing to come back in 2 weeks because they don't have any techs available. So why the F did I need to come now?.... They are going to bombard it with all the NVH analyzer sensors all over it, then evaluate.

 

Haven't tried towing (on the highway) yet, but I'm getting the same vibration in my brand new 2020 2.7L Lariat SCab. Brought it in, they balanced the tires. NO BETTER, as I suspected since it felt totally drivetrain related. Took it back, they said that they couldn't find anything wrong and after trying another truck on the lot they confirmed it did the same thing. They suggested that it "might need some more breaking in". Very unhappy.

 

Mine does this as well. Waiting on my 5th service appointment. Tires balanced twice, Winter wheels and tires also vibrate. All 4 rotors machined, new driveshaft. No change at all. The litmus test on mine is to put 500lbs in the back of the bed, and lock out all gears. Accelerate in 1st - wicked wobble vibration in the first 30 feet.

 

Look here, may be the cause of your vibration issues.

https://www.f150forum.com/f118/drive...-found-428699/

 

I've been telling the dealer to start there, but they seem to want to spend a lot of Ford's money fixing stuff that doesn't solve the problem.

 

Inquire if they have a NVH analyzer. Tons of sensors deployed all over the truck, and it will discern the vibrations frequency and would help them look at specific components. The analyzer plugs into the obd so it knows vehicle speed/rpm/gear etc then it knows what rpm all the parts are spinning and correlates with the vibration frequency to give a better pinpoint. All the different spinning parts spin at different speeds and would have a matching vibration frequency and supposedly the analyzer takes all that into consideration.

My money is on rear axle assembly, or driveshaft since the extra load of a trailer amplifies.

 

Not sure if this helps, but when I tow I fill the tires to max psi. That in itself give a whole new feel. The roads will impart there own vibrations at times. But towing my 6k trailer with loaded bed I don’t feel any constant vibrations. I did upgrade shocks,tires and added air bags