Suspension Gurus, please step in here!!!

[unclehoser]

Once again, the new guy needs advice! Truck is a 2002 F250 SD, 7.3 Powerstroke, ZF-s6 trans.

Problem is a serious one regarding stability. I have had several instances, most often in a slight right-hand turn at speeds from 30 to 60 MPH, where driving across a slight depression in the road (pothole, manhole, etc.) sends the truck into what can only be described as an "oscillation". It shakes like a leaf in the wind, and feels like the whole damn thing is going to disintegrate! It doesn't seem to be all that noticeable in the steering wheel, as I still have control. After slowing to a speed below 25 MPH or so, it stabilizes and I can go my merry way (with quite a load in my shorts, to say the least!). It feels more like the entire suspension is oscillating, rather than just the front end/steering gear. Kind of a 'diagonal' or 'corner-to-corner', sideways shake.

I replaced the shocks (they were toast, anyway) but the problem still rears its ugly head. Trust me, it's a panic situation! Other vehicles near me scramble to get the hell out of my way!

What can cause this type of malfunction? Where do I look first? What can I inspect, and how do I go about that? My nerves are shot to the point where I do slaloms around manholes...and that don't look good to the cops!

As always, the advice received here is much appreciated. I'm still learning new tricks...

Cheers!
Dave

 

[79jasper]

Well, still sounds like death wobble.
Check all front end components.
Does it have a steering stabilizer?

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[towcat]

deathwobble.
check all suspension links. braces and bushings.
also. Rotate tires first. no cross rotate. just same side front to rear, rear to front.
report findings.

 

[unclehoser]

Well, still sounds like death wobble.
Check all front end components.
Does it have a steering stabilizer?

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As far as a steering stabilizer, I have no idea. I'm fairly ignorant when it comes to front ends and such. The term "death wobble" has come up a couple times in conversations with friends, but none of them are really all that familiar with the particular vehicle in question.

Checking front end components is beyond the scope of my knowledge! I don't even know where to start! I did replace the shocks, which was a good thing. The fronts collapsed with hand pressure and didn't recover.

 

[unclehoser]

deathwobble.
check all suspension links. braces and bushings.
also. Rotate tires first. no cross rotate. just same side front to rear, rear to front.
report findings.

Tires were just rotated about 3 weeks ago, front-to-back. The problem had not presented itself before then, but I don't think it's related. Tires have only about 5K miles on them. I did notice a bit of wear on the outer treads of the rear tires (which were on the front before this all began...). That prompted me to look at shocks, and all 4 were replaced a week ago.

 

[79jasper]

Steering stabilizer will be a shock mounted to the drag link.
The SD era trucks did something a little different than the OBS and death wobble was more common.
Basically have someone turn the wheel back and forth while you look at everything. If there's any play you'll know it.
Then jack it up and check the ball joints. Grab the tire at 12 and 6 and try to move it up and down.

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[goldsjos18]

if you are looking for a video explaing it bill at powerstrokehelp.com did a video about death wobble just look him up

 

[79jasper]

Oh Lord, not another bill ****** fan. Lol

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[goldsjos18]

Oh Lord, not another bill ****** fan. Lol

im not necessarily a fan im just trying to point out that his video goes over a few key points.

 

[Thewespaul]

You must be registered for see images attach

Caption this

The expressions in all of the thumbnails of their videos are hilarious to me idk why.

 

[Double-S-Diesel]

sounds like death wobble
id look into the track bar bushings

 

[towcat]

Tires were just rotated about 3 weeks ago, front-to-back. The problem had not presented itself before then, but I don't think it's related. Tires have only about 5K miles on them. I did notice a bit of wear on the outer treads of the rear tires (which were on the front before this all began...). That prompted me to look at shocks, and all 4 were replaced a week ago.

let me get this right......
you rotated tires three weeks ago and the deathwobble problems started shortly after rotation?
please affirm/deny.

 

[unclehoser]

let me get this right......
you rotated tires three weeks ago and the deathwobble problems started shortly after rotation?
please affirm/deny.

That's correct. I had never experienced it prior to that point, although I just might have not been driving in the right set of circumstances. It hasn't happened with the wheels pointed straight forward, only when I'm into a SLIGHT right-hand turn, like a mild curve or lane change. It has only happened when the left tire contacts a small depression in pavement (there are quite a few manhole covers that are slightly below grade in my location, after ****** repaving of the highway). I've experienced it 4 or 5 times now, at speeds from 30 to 60 MPH. I can't confirm whether or not tire rotation was a factor, only that it first presented itself shortly thereafter.

I'm really not a great mechanic, and, at my age, laying around on concrete, working over my head on a truck suspension will be painful as hell! Changing the rear shocks 2 weeks ago was bad enough, and it wasn't even that difficult! I'll probably take it to a local shop with a great reputation for honesty & fairness (been there before, and liked what I got) and have it checked thoroughly. He won't do alignments, but I can have that taken care of at one of the tire shops and tell them to pound sand when they try to sell me all the "defective" parts that I just had replaced!

Any and all suggestions are greatly appreciated. You folks DO know your stuff, that's why I ask here first!

 

[towcat]

do me a favor. rotate the tires again and see if the problem still exists.
please.

 

[79jasper]

Yep. Do that first.

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