I'm curious if anyone else's truck exhibits these symptoms, and if you had it dealt with. Mine has been doing it for a long time. I don't think it's actually gotten worse, but now that some roads were repaved on my work commute I'm starting to notice it more.

Slight vibration felt in the steering wheel and sometimes seat, when:

• Speed is 40-50 MPH (worst around 47 MPH)
• Truck is coasting (even very slight throttle input makes it stop)
• Truck is in gear (shifting to neutral makes it stop)
• Driving on a smooth road (bumps and pavement imperfections tend to hide it)

The following have no effect on the behavior:

• Feels the same in 2WD or 4WD (4A or 4H)
• No change when going around corners vs straight
• No change when braking
• No change in different gears (manually upshifting or downshifting)
• Rotating tires changes nothing

If I get the truck up to 55-60 on a smooth road and let off the throttle and let it decelerate, I can feel the vibrations start around 50 and disappear around 40.

I don't think it's transmission related - a friend had a 6R80 that did something kind of similar and a fluid change fixed it. I had the dealer flush the transmission fluid recently as a preventative/mileage thing and it changed nothing. I also don't think it's tire related since a rotation changes nothing and I don't see how throttle input would impact if it were a balance issue there. I was thinking it may be driveshaft related, like a balance issue or u-joint going bad.

 

I had the exact same problem. Took it to the dealer and they determined it was the rear end. They replaced the ring and pinion gears and the carrier bearings. The problem went away. Many years later I have a similar problem. Now when under slight acceleration it has that feel. I think it's more annoying than detrimental. I just learned to live with it.

 

Thanks! My dealer is waiting on an APIM for my truck (current one is super slow and failed a self test), so I may have them look at this while they have it for that. I have a Ford ESP for a little while longer that should cover it.

Funny thing, my front differential was already rebuilt at around 40k due to a wheel bearing-like noise. It's wild that there's a chance I'll need two differential rebuilds inside 75k. I love this truck, but the list of issues I've had sometimes makes me want to try Toyota again.

 

I had the rear rebuilt at around 15,000 miles. Ford said the the pinion preload was out of spec and excess backlash

 

Try this and see if it makes a difference just for diagnostics.
Use a spray can of Silicone Lube liquid, not foam type.
Flood the rear drive shaft cross joint. Give it some time to penetrate the joint cap Bearings area and try it out.
Might try the front joint as well separately to see.
I had/have a very slight shake at 60 mph and flooding the rear joint has stopped it on a temp basis. It may come back later requiring joint replacement. The vibration was also variable in and out depending on road surface smoothness.
It seems to have an Rpm and drive loading sensitivity plus road surface to start it if the cross joint needles are dry of lube and beginning to angle bind in one location repeatedly as the drive shaft turns. Just my thoughts on it.
Wheels were balanced two times at different shops made no difference on new tires as well as old ones.
Time will tell.
Good luck.

 

I had the same exact symptoms, vibrating at speed, neutral made it go away... went through 2 dealers to find one who wouldn't blame the tires... they found the carrier had runout where the ring gear sat.. ended up replacing the whole innards minus axles. that was at ~18k miles. vibration is gone, but occasionally I get a hopping sensation from the rear... can't tell if it is the roads or something with the rear... possibly a bad u-joint from the vibration.. just going to run it until it gets worse or breaks. looking around it seems it's only the 3.55 locker that has these issues.

 

I had similar symptoms on my 2018 back in 2021. Dealer diagnosed a bad driveshaft. Replaced-it under warranty. Problem never came back.

 

Thanks, everyone. Sounds like there's a good chance it's either driveshaft or rear differential related, which makes sense based on the symptoms. I'll see what the dealer says. The positive is I have pretty good confidence that they'll accurately diagnose it - they were excellent with the front differential bearing noises a couple years ago.

 

It's best if you can get the tech in the truck with you to reproduce the symptoms for them. I had to have the head tech ride with me to show exactly when the vibration occurred and what made it go away (shifting to neutral).

 

I had something similar at about 60 mph. Wound up being the driveshaft center carrier bearing. You cannot replace the carrier bearing on the stock driveshaft so I opted to get a new driveshaft from Fort Wayne Clutch with a replaceable bearing. They were a great company to deal with.

The info on that is in this post..... https://www.f150forum.com/f118/2016-...6/#post7280142