I recently purchased a used 2010 F-150, XLT, 5.4L, SuperCrew with the FX-2 package (so it is Rear Wheel Drive - not 4WD). It has 120,000 miles. As far as I know, everything is original.
Here are the 2 problems I'm experiencing:
-- 1. When coming to a complete stop, there is a subtle thump that occurs just about the same time the truck completely stops. When I release the brakes and idle forward, everything seems normal. But, when I press the accelerator slightly, I feel that same thump. It's almost like something is engaging or disengaging. But, I can't tell if it is in the transmission, torque converter, brakes, etc. Anyone have any thoughts?
-- 2. When riding between 50 and 55 MPH, there is a vibration/shutter that occurs frequently, but not every time. It's almost like riding on a washboard. Anyone have any thoughts?

 

https://www.f150online.com/forums/ot...line-lube.html

https://www.f150online.com/forums/20...-mph-help.html

Read these. Should answer both of your questions. ��

 

Thanks for the links...I'll read through them

 

If you have a ls diff it could be the clutch packs gone bad. The vibration is caused due to the slip in speed when cornering. Outside turns faster as inside turns slower.

 

Am I too old fashioned to think it sounds like a u-joint on the driveshaft?

 

I'm not the best mechanic, so my thoughts here may not be correct. But, this vibration occurs when traveling on a straight road at 50 - 55 MPH. So, I'm struggling to understand how going around a curve would contribute to this vibration. A detailed explanation might help me understand a little better.

Thanks...

 

That was my firs thought, too when I noticed it. But, when manually trying to turn the drive shaft, I don't feel any play. Plus, the sound is not quite metallic...it's more of a thud than a clunk. If that make any sense?

 

What I read, in the link above, regarding the vibration at 50- 55 MPH, sounds different than what I'm experiencing. my vibration is no where near as "violent" as is being described in that thread. My vibration is relatively subtle...if I'm distracted by other things, like a good song or heavy traffic, I don't notice it.

 

Well the driveshaft spline slipping back and forth is what would be making the thumping. Moving it manually by rotating or whatever other means, unless it is a much worse case scenario, probably won't produce the thud you're speaking about. I know mine didn't either. But mine was fixed when I had to have my driveshaft replaced due to the support bracket breaking off at the weld and jacking up my driveshaft. But new one went in and no problems since. Pretty much the same as what everyone else that got theirs re-greased said.
Same thing with the bed vibration. Was never terrible, but noticeable. But once I put my toolbox on the bed and added a s*** ton of weight in there from my tools, aircompressor, and other miscellaneous items I have not noticed it since. Maybe I'm way off from your issues, but just speaking from my personal experience with these problems. Good luck figuring yours out!

 

The newer u-joints are not the same as the old ones. I may not be using the correct terms, but you can't just take a few hand tools and change them anymore. I think my mechanic friend told me they have some type of epoxy in them, and have to be cut out. What I am getting at is, just manually feeling of it may not be the same as it used to be.

 

Thanks for all the input.

I think greasing the driveshaft spline just might be the fix for the thump. Even if it isn't, it doesn't sound like it is too much work or money, so certainly worth trying.

As for the vibration...I've often thought it might be a tire, or perhaps a wheel out of balance or maybe even a suspension characteristic combined with the lack of weight causing a funky "resonation". But, I've mentioned this to others, and someone mentioned a TSB that calls for a tranny reflash to correct this issue. So, I was hoping there was some history of this type of problem that might help give me some direction. If it's not drive train related, I can learn to live with it...I just don't want it to turn into something more serious later on. If I figure it out, I'll be sure to let everyone know.

Thanks again!

 

***UPDATE***

Greasing the spline gear in the driveshaft solved problem #1 I described in my original post.

As for the vibration, as described in problem #2 - I haven't tried anything yet. I need new tires (20"), and I have a lead on new wheels AND tires for $750. So, I'm waiting to get those new ones and have them balanced and mounted to see if that helps. If it doesn't, then I'll pursue other ideas.

 

A good wheel/tire balance could get rid of the vibration at 50-55.

I had a rear drive 81 Ford Granada back when and it had the vibration. I drove the service foreman at the local dealer mad taking it in to get it fixed. In the end, the best they could do is to balance the tires on the car and got rid of most of it. I had a 79 V8 Mustang and I switched tires and wheels from car to car and the vibration stayed with the Granada. the dealer also tried the same thing with a new 82 Granada. At that time, an engineer I worked with went through a similar experience with a new Buick. He found out that on a rear drive car, there is an inherent imbalance that can't be engineered out. The Granada and Mustangs, fox bodies, of that era had a weight just about the pinion that was supposed to move the vibration to a higher speed where you wouldn't notice it.

That Granada is the only vehicle (out of more than 50) I've ever owned that had that vibration that was noticeable.

 

Hey I know I'm late but I have an answer for number one if you haven't fixed it yet. I just picked up a 2010 5.4 fx4 with 90,000 miles. When coming to a stop it felt like there was TV sliding back and forth in my bed. This is only from 2nd down to first. I thought it was a tranny issue or a reared end issue. Well turned out the tranny had to be reset and now I can barley even feel the shifts. As for your second question I'm not sure

 

***UPDATE***

Reference post #12 of this thread for the fix to problem #1.

The vibration that is described in problem #2 of my original post, seems to have been solved with new wheels and tires. Occasionally, I "think" I feel some kind of vibration, but the circumstances are not quite the same, and what I "think" I feel is not as intense as it was. So, for now, I'm considering the problem fixed.

Thanks to everyone for there help!