Sorry if this was beaten to death but I did not find any resolution to this yet from reading other threads. I experience a vibration/shudder low rpm mostly 5th/6th gear (40-55mph). It doesn’t coasting down hill or if not
on the gas. It only does it when I’m barely touching the gas pedal on a slight incline or flat road. I changed the spark plugs with OEM and no change. It is a 2016 5.0 ext cab 6.5’ bed with 120k miles.

 

You're practically lugging the 5.0 at those speeds when in 5-6th gear. Put it in sport mode and I'll bet it stops. That or try giving it some gas so it will down shift...

 

It still shouldn’t shudder as hard as it does.. I have 18” wheels - 33’s on it. Other than that, it’s stock as far as performance. Cake factory with 3:55 gears

 

There are many threads on here about vibration and shudder issues. I have a 2016 5.0 and noticed them on day 2 of ownership. I had a vibration at the low end of 5th and 6th gear and a vibration decelerating around 30mph. I also had a shudder at hwy speeds just as you hit the accelerator to pass someone. First off, the dealership try to pass it all off on being "new" give it time to break in they said. Back at 5000 miles same issues. They changed, rims, tires, driveshaft and installed a completely new real axle assy including the case (all of it). It did nothing and told me my vibes did not surpass their standards so enjoy the truck. I went back and forth with them for months. At one point they installed a shim kit on the springs and told me it fixed the problem. It did not fix it. It did however move the deceleration vibe from 30mph to 20mph. I gave up and tried to lemon law the truck. I lost my case because in the eyes of Georgia my truck does everything a truck should do and it is not a safety concern. The Ford engineer stated the truck does vibrate but also stated many vehicles vibrate. Recently a new service manger took over and I ask him to look at my truck again as it is still under warranty. They replaced the torque converter, which did solve my hwy speed shudder. My truck feels like a Lincoln now past 50. They also changed my driveshaft again. Now I have a constant but "lesser" vibe from about 40-50. I don't think anyone has a cure all for the F150 vibration problems. Not all have them but many do. Good luck.

 

my 18 5.0 does the same thing, all it get is the run around from the dealer, can reproduce... complete BS. I'm starting the buyback process today for this and another issue. (oil usage on two different engines)

 

So the torque converter was installed a different time than the driveshaft? Im just trying to make sure it wasn’t a combination of both. It isn’t a constant vibration shudder, only intermittently. I guess I’ll try to find a cheaper torque converter

 

Just got my truck back from the dealer for the 40-45 mph shudder. Dealer drove it 19 miles and said they felt nothing. I drove the service manager around the block. The truck vibration happened, of course, but the service manager just said, "Feels normal". So, no fix for me on that.

 

The TC and Driveshaft were changed at the same time. My hwy speed shudder upon acceleration went away. I am 100% confident the TC was causing that problem. My low speed vibes changed but are still present so I am not sure what effect the driveshaft had. A shudder feels like you are running over rumble strips really quick. If that is one of your concerns maybe the TC is the culprit.