I have a 2014 Supercrew with the 5.5 foot bed, which has a pretty noticeable vibration. I would say it is felt mostly in the seats but can feel it slightly in the steering wheel too. From time to time I notice at lower speeds but it really kicks in at around 52 to 53 mph and is most constant and worst at 60mph, and at 80 might even be a bit worse. I noticed it when I test drove it before I bought it and mentioned it to the salesman and he said it felt like one of the new tires they put on wasn't balanced correctly. When I picked it up it was supposedly fixed and they had found one tire that wasn't balanced correctly. When I drove it home, same vibration. They brought it back in, they road forced balanced all 4 tires and they all were out of spec. ( Goodyear Wrangler SR-A) They warrantied all 4 and got a new set and put those on, nothing changed and they all pass the roadforce but 2 are a bit on the high side but not out of range. This was all at a GM dealer I bought from.
Next plan of attack was to hook it up to the picco machine(supposed to pin point where vibration is coming from. The Ford dealership did this in town, called me and said the drive shaft was out of balance, sent that out and put back in, no change. Then they thought maybe I had a weak shock, they replaced both in the rear. Also I had them pull the rear axle shafts and run them out, checked good. At this point I was a bit fed up that this was this hard to find and told them I was going to drive for a while and come back in a couple months. I did read somewhere on here where someone had kind of the same kind of deal and if I remember it was the rear electronic diff locker.
Any one else experiencing any of these same symptoms. I do not like the goodyears I have heard the sidewalls are too weak but I couldn't get them to replace with a better tire due to warranty. Oh the truck has about 94500 miles now, has the 3.55 rear end.
Any suggestions would be greatly appreciated.
Thanks
Matt

 

I have a very similar issue, 55-70 mph is when it's the most noticeable for me. Though lately with the cold weather I usually don't notice it until 60 mph. I have a thread going that I posted about 2 weeks ago, on this forum. I too noticed the vibration when I first test drove the truck, from a Chevy dealer. Of course I figured I could eventually fix the vibration issue so I had no problem buying the truck, and luckily it has not gotten any worse. It's a vibration that is enough to be noticeable but it does not shake the truck. Is that how your vibration is? Mine has 71,000 on it now, it's a 2013 FX4 cclb. I bought it in June 2018 with 64,000 on it. I originally was thinking that it had to be in the drive train or the rear differential, but I need to check the parking brake and make sure it isn't sticking. That could cause the vibration. Also, it's interesting you mentioned that someone had to fix their electronic locking differential to fix their vibration issue. I wonder if this problem is most common or is exclusive to trucks with the locking diff?

 

Yes it is the same, doesn't completely shake the truck but it definitely more of an annoyance. Felt in the seat and kind of annoying if you want to use your headrest. As far as yours, you have the 6 and a half foot box, Im guessing you have a 2 piece drive shaft? If so I have read a few guys posts about having to rebalance and change out all 4 yokes on those, possibly the carrier bearing too. I am going to pull my front drive shaft for the 4x4 and just take that out of the guessing, not sure when but I will let you know if it changes anything.
Thanks

 

I do have the 2 piece drive shaft, I know the slip joint needs to be re-greased with the grease kit from Ford. I have a mild clunk sometimes when going into park or just when going really slow. But I do not think the slip joint is the culprit, although its possible. I have read that greasing the slip joint does not fix anything except the clunk issue. Also I loosened the parking brake on both sides and it did not seem to make the vibration go away. I don't think that pulling the front drive shaft will change anything, it is not turning if you are in 2WD. The front CV joints are turning in 2WD but not the driveshaft, unless you have automatic 4x4.

 

I have done more research into this the past few days, you need to check the drive shaft angle in relation to the pinion flange. Also check to see if there is an imbalance in the drive shaft, maybe a weight has fallen off of it. Also, check for bad u-joints. Even one that does not have any slop car still cause a vibration. Sometimes the u-joint end caps need shimmed as well. Here is a good write up from the superduty forums. I am on vacation this week but I may still look at my drive shaft again and check u-joints. I'll get back to this thread and post if I find anything. Also, are any of your brake rotors warped. I noticed that my left rear rotor is warped I am going to either have it turned or replaced then see if that fixes the issue.

https://www.brakeandfrontend.com/sus...ion-diagnosis/

https://www.ford-trucks.com/forums/1...vibration.html