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Vibrating between 43 and 54 MPH

Hi all, I have a 2007 F150 STX 2 wheel drive that vibrates between 43 and 54 MPH only. Very consistent and it doesn’t happen every time, but I’d say above 90 percent of the time. Now I’m getting the run around with mechanics about what the problem is. I can see the bed of my truck vibrating and I can hear it, sounds like I’m driving over rumble strips.

I had the transmission, transmission cooler, a coil pack, intake manifold, and throttle body replaced by the Ford house in January of last year. The shaking began a few months after the replacement. I had the tires rotated. No change. I had the tires replaced, no change. A few months ago the front left wheel bearings and both lower ball joints were replaced. No change. It has not gotten any worse or better, and every mechanic I have talked to has claimed something different but it’s all theory because they can’t figure out what it is, they just want to start replacing things without being sure.

I’ve heard:
Center driveshaft carrier bearing
Torque converter shudder
Bad suspension

Turning off overdrive makes no difference.

Thanks in advance, Chris.

Given what you’ve already done, & presuming the tires are good & measure perfectly round, the wheels are properly balanced, and the alignment is spot on, those three ideas above seem like the most likely suspects. I think most likely it is one of the first two on that list. There was a truck owner here maybe a year ago who had a similar problem, diagnosed finally to be the carrier bearings. You might search this forum, see if you can find that thread. Turned out as I recall nothing actually wrong w/the CB, just wasn’t adjusted properly so it was binding the driveshaft. I expect you’ve got something similar going on, some kind of driveshaft vibration. It’s possible when the prior work was done, they forgot to place witness marks and so didn’t install the driveshaft w/the same orientation. Next step is probably a visit to a driveshaft specialty shop. They’ll remove the driveshaft & test it on a machine for balance.

Considering Ford’s history of torque converter issues I feel they should have replaced the converter at the same time as the trans and the fluid cooler.

You might consider having the U-joints checked. Some consider the joints good if tight and that is not a definitive test. The driveshaft needs to come out and the joints worked by hand to determine if there are any flat spots in the bearings. This applies especially to the front joint as that is the one most prone to problems.

Maybe they didn’t mark the driveshaft and reinstall it in the original orientation? Sometimes that can be a problem.

It’s really funny that you mention the witness marks because one mechanic pointed out the witness marks being off on the half shaft (rear side of the carrier bearing) where the slip yolk and shaft meet.
I showed my trusted mechanic this discrepancy and he said he doubts it being an issue because it didn’t immediately vibrate for almost 2 months. Do you think he’s wrong?


Edit: There’s another possibility you’ve reminded me. Sometimes the slip yoke doesn’t slip correctly, binds. The symptom folks complain about is usually a “clunk” when stopping or starting. But I suppose it could cause a vibration also. There’s special synthetic grease available that is claimed to cure this problem. Worth a try anyway.

Excellent. Is it normal for the rear end shaft to be pulled out when replacing a transmission?

@ok4450 I’ll call the Ford house Monday and ask if they replaced the torque converter. I would assume not.

I was getting a “thud” when starting and stopping, but that was before the transmission was replaced. Haven’t had that symptom duplicate.

I’ve never replaced a truck transmission. But I’ve changed u-joints on my own truck’s tranmssion and when I do that I’ve always just removed the entire driveshaft between the transfer case and the differential and worked on it on the bench. I expect they do the same thing when replacing the transmission.

Edit: Even when I remove the entire driveshaft, which has slip-spline arrangement separating the back from the front, I’ve never had to remove the front part from the back part. I just leave it the way it is, so no need to put witness marks there.

Well I hope the vibration from the driveshaft hasn’t caused any damage to anything it’s attached to. I’ll call the dealership Monday and ask if they remove the entire driveshaft when pulling transmissions. Maybe I can get a free adjustment since it would be their fault I would think.

Suggest to ask if they have the equipment to check drive shaft dynamic balance. If so they can remove your DS from the truck & install it on the test equipment and spin it up and check for balance problems. And if they aren’t equipped to do that, would they work w/ a local drive shaft specialist who can take a look at the situation. Google “your city driveshaft specialist”.

Just guessing here but I would think if a mismatch of the witness marks was the problem , it would have shown up immediately , not months later .

I suggest the U-joints because on multiple occasions on Fords I’ve owned the joints were tight but in every case the front joint was at fault.
I’ve also run into this on other Fords not owned by me. Went through this not long ago on my daughter’s '05 Mustang also.

My opinion (right or wrong) is that the front joint is the closest to heat sources; meaning the exhaust pipes and the rear of the transmission itself. Over time that leads to degrading the grease in the joint faster. The needle rollers then start dragging and develop flat spots which in turn cause roughness. This cannot be detected with the shaft in place but can be easily felt with the shaft out and manipulating the joints by hand.

Yes, the shaft must be removed to replace the transmission. They should have checked the U-joints at that time assuming they did not.
With this much lapsed time they may not want to provide any consideration to you though IF the joints turn out to be faulty.

As for torque converter shudder that is common with Fords. In most cases a fluid change will cure it. In your case fluid condition should not be an issue.
The Ford converter shudder is usually prominent around 35-50 MPH and does resemble the rumble strip feeling. Hopefully it’s not a converter issue.

Unfortunately there aren’t any driveshaft shops out here so I went to a transmission shop, the mechanic was extremely friendly and he drove my truck, he said he’s not sure what the vibration is but he can feel it, he wants to look at it tomorrow so I’ll be dropping it off in the morning, hopefully he can figure out what it is. The vibration is worse some days than others, and today it wasn’t as bad as it can be. Transmission fluid looks good and is full.

If you have a shop that can safely lift the entire truck, that may help. You’ll pay for some labor, but you won’t pay for parts you don’t need.

I had a van that was doing the same thing, so I lifted the van up and started removing things.
run it in the air. Vibration still there?
Tires off. Vibration still there?
Driveshaft off. vibration still there?

mine ended up being an out of round tire.
Good luck!

The vibration you feel might be caused by tire bounce from worn rear shocks.

Here’s an example of tire bounce.


Great news, the mechanic saw the witness marks that were off and the most rear u-joint was not aligned with the other u-joints. He realigned the rear drive shaft and now the extreme shaking and vibrating is gone. Woohoo! After a year of this I’m finally rid of it.

Thank you all for the help! I’ll show a picture of the witness marks when I get time.

Well never mind, cancel that. The shaking came back and it is more of a bounce in the rear end, so maybe rear shocks?

He says he doesn’t feel torque converter shudder and the transmission feels great to him.

I’m thinking:

Bad center driveshaft bearings

The center shaft brearings would be cheaper to troubleshoot I’d think?

Something else: the vibration is now between 47 and 55 exactly since realigning the rear driveshaft. Is it possible I have bad shocks and bearings?


Have someone follow you in another vehicle when you get to those speeds, to see if either of the rear tires start bouncing.


Ok will do. Is it odd that it’s not consistent or is that not surprising?

No. It’s not surprising.

All it takes is hitting the slightest bump at the right speed to get a tire to start to bounce when the shock/strut is worn.