2008 F-350 slight vibration

[TravisP2001]

My 2008 F-350 6.4 Powerstroke has a slight vibration almost like it is a little bouncy when you first accelerate from stopped and when you slow down. It goes away when you are over about 30-40 mph. I checked the rear driveshaft and did not feel anything in the u-joints or center bearing. My next step was to disconnect the front shocks to see if they are bad. It almost feels like it might be bad shocks reacting to the aggressive mud tires on the truck.

At first, I thought it was something in the transmission. I had recently had a transmission line blow out on me when I was pulling my 5th wheel. I changed all the lines out and replaced the filter in the pan. But the vibration does not seem to change at all when gears change or when RPM goes up and down.

Just looking to see if anyone else has had similar experiences or not.

 

[6.0 Tech]

Is the vibration in the steering wheel or the seat? And is the truck lifted?


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[TravisP2001]

Is the vibration in the steering wheel or the seat? And is the truck lifted?


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I can feel it in the steering wheel but not real strong and the dash. It is not lifted.

 

[6.0 Tech]

Have you had the tire balance checked? If it’s vibrating at say 30, it should vibrate at 60 as well. Is there goofy wear on the tires, like cupping or anything like that? A front vibration is odd on take off. Any weird front end feel? Like wandering or looseness or anything?


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[ncollins64]

Sounds crazy but check for slipped belts in the tires. I’ve personally had that happen to me before with the same symptoms you are having. Also for s&g’s, check all your front suspension and steering components for slop

 

[TravisP2001]

Have you had the tire balance checked? If it’s vibrating at say 30, it should vibrate at 60 as well. Is there goofy wear on the tires, like cupping or anything like that? A front vibration is odd on take off. Any weird front end feel? Like wandering or looseness or anything?


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I have not had the tire balance checked. I have the 4 stock rims with almost new tires on them. The guy I purchased the truck for them had upgraded the rims and tires but still had the old ones and included them with the truck. I have thought about changing them to see if it would make a difference. The main reason I think it is not tire related is the way it basically goes away after I get over 35 or so mph. I have looked for bad spots on the tires but can't find anything. I have had that happen to me before on my Expedition.

I did remove the steering damper recently when I changed the AC Compressor. BTW, That is one of the hardest AC Compressor change outs I have ever done. I need to get back under there and just make sure everything is good with the steering damper. But I would not think that would cause this.

I also plan on changing the cab mounts. I have them at the house in a box. It was something else the guy I got the truck from had already purchased but never got around to changing all of them. He only changed two of them. I have thought that maybe that is the issue.

I am pretty convinced it is nothing in the transmission or engine since RPM really does not have any effect on it. It is just at low speeds under 35 or so. And not a constant the whole time either. Even does it when coasting to a stop. And it is not a really bad vibration either. Just a slight vibration. Shakes the dash and steering wheel just slightly. To me, it almost feels like I would imagine it would feel like riding on one of the mud tires with nothing to soften the bumpy feeling from the tire tread.

 

[TravisP2001]

Sounds crazy but check for slipped belts in the tires. I’ve personally had that happen to me before with the same symptoms you are having. Also for s&g’s, check all your front suspension and steering components for slop

When you had issues with the tires, did it go away at higher speeds?

 

[ncollins64]

Yea the driver front tire had a bulge in it that I didn’t see from slipped belts. It only shook around 30-40ish mph then it went away once I got to higher speeds.

 

[jschildm]

Hub locked in or stiff that turns at lower speeds but doesn't at higher speeds?

 

[TravisP2001]

Hub locked in or stiff that turns at lower speeds but doesn't at higher speeds?

Hubs are in auto. The passenger side hub is hard to turn from lock to auto. Had to put a wrench on it to turn it to auto. The guy that owned it before me had one side in auto and the other side in manual. Figured that out when I needed 4WD a couple of months ago.

 

[psduser1]

A stiff axle ujoint will cause this, locked or unlocked. Found that out the hard way.

 

[jschildm]

Hubs are in auto. The passenger side hub is hard to turn from lock to auto. Had to put a wrench on it to turn it to auto. The guy that owned it before me had one side in auto and the other side in manual. Figured that out when I needed 4WD a couple of months ago.

Auto hubs can stop functioning correctly, but usually they stay unlocked no matter what, though I have heard of them rarely getting stuck on. Could try spinning the drivelines with the wheels on the ground to confirm they are both actually unlocked, but likely not a the issue.

A stiff axle ujoint will cause this, locked or unlocked. Found that out the hard way.

That was my next thought as well. On mine it eventually got worse and it started pulling the wheel around some. Might be able to compare the ujoint temps left to right after driving a bit to see if one is warmer than the other.

 

[TravisP2001]

I finally got the problem fixed. It was the U-Joint closest to the transfer case on the rear drive shaft. I did however go ahead and replace all three joints on the drive shaft as well as the center support carrier bearing. The U-Joints were a PITA to remove. two of them I had to end up cutting the center part out with a cutting disc and side grinder so I could push the end pieces out with a bearing press. The retaining clips were so rusted and brittle I could not get most of the off. That is why I had to cut them out like I did.