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Old 01-02-2017, 10:54 PM   #1
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Death Wobble Revisited

Just got back from a west coast round trip from Seattle to Orange County. It was about 2899 miles of picturesque worry free driving and 1 mile of white knuckle sheer terror somewhere in the hills above Santa Barbara thanks to the infamous death wobble. Luckily I knew that it was about to come on strong and I was able to downshift and pull over in time.
I have my own theory about this that is different than other experiences that I have read about. I have personally put on 12k miles on my van and besides this latest episode, I have experienced the death wobble 2 or 3 other times in exactly the same spot near my home in Seattle. For me, it takes the right grade, descent speed and road surfaces to make the death wobble come around. During my recent west coast trip, I encountered steeper grades, faster descents, crappier road surfaces without any hint of wobble but if the ingredients show up right, it leads to a scary few minutes of driving.
I was hoping to get some new rubber on my van before my trip but ran into some technical problems with the wheel/UCA geometry. I am hoping that may solve the problem in the future.

Happy new year everyone and happy trails!
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Old 01-02-2017, 11:32 PM   #2
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I have a 99 E350 Quigley SMB and used to have a bad case of death wobble. Usually when braking at around 40 mpg on a downhill grade. New trac bar fixed my issue pretty well. I still get a slight shake due to what I think is my rotors but no death wobble.
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Old 01-03-2017, 10:26 AM   #3
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I thought the "death wobble" was associated with some sort of solid front axle / 4x4. From your signature, it looks like you have a 2wd Savanna and as you mention, has A-arm suspension.
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Old 01-03-2017, 02:59 PM   #4
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Its definitely a 2wd and a death wobble. No doubt about it!

Anyone have any recommendations for a steering/alignment shop in the Seattle area?
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Old 01-03-2017, 03:14 PM   #5
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"Traditional" death wobble is normally a solid front axle shifting side to side, often due to bad tracbar/bushings/mounts, ball joints, or other front suspension issues.

It's extraordinarily violent.

I'm no expert, but if your independent 2wd is doing something like it, you need more than an alignment, something is wrong..
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Old 01-03-2017, 03:34 PM   #6
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Supersporttramp -- how many miles are on that GMC of yours? You said you've put 12k on it yourself, but its not clear immediately if you're the original owner (and if not, what the total mileage on that van is.) Wondering how worn the various tie rods/ball joints/bushings might be in your van, and if that isn't the logical culprit if the van has higher-mileage on it.

A lot of worn-out joints can actually act totally fine most of the time while the vehicle is loaded up and driving along on smooth pavement.....but when a sudden jolt to the suspension happens (especially if the suspension is side-loaded somewhat, on a long curving stretch of freeway), the joint can swivel unpredictably and create all sorts of oscillating suspension movement (and radically changing/swinging steering geometry). I had an idler arm that was going bad in an old Dodge sedan, and it wasn't totally obvious until I hit a bump while on a stretch of swerving highway. Car nearly dove into the ditches, and it took a lot of effort to get the car back under control before it settled back down. $30 at a NAPA auto parts later for a new MOOG replacement and everything was good to go.

As others have mentioned, its pretty odd for a factory-stock 2WD front end to display death wobble, unless there's a component (or components) that are out of spec.

Also -- to this comment of yours:

Quote:
Originally Posted by Supersporttramp View Post
I was hoping to get some new rubber on my van before my trip but ran into some technical problems with the wheel/UCA geometry. I am hoping that may solve the problem in the future.
Is this wheel/UCA issue you mention something completely separate from this "death wobble" issue that you're experiencing? (I'm guessing the wheel/UCA issue is indeed a separate item, solely related to you wanting to put wider tires (and perhaps a new/different wheel offset) on the van, and running into issues where its going to crash the inside edges of tire/wheel into upper control arm.)

Might be worth investigating the integrity of all the ball joints/tie-rods/idler arms/pitman arms/steering box/etc with a respected suspension shop before going to a larger tire size. Larger rubber will usually only magnify problems that exist in a front end, not make them better.....

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Old 01-03-2017, 05:19 PM   #7
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Thanks for all the tips Mike. I will get the van to a shop in the near future. I'm the 3rd owner. Van has 30k total miles now. Most of it highway miles. Its been kept bone stock all along.

The wheel/UCA is a totally separate endeavor in trying to get larger tires on the van.
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Old 01-03-2017, 06:02 PM   #8
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Whoa....that's still a young pup! At only 30k miles, that front end should still be almost like new (and should drive essentially like new.) Something is definitely amiss....starts to get the questions rolling such as "is the van loaded unevenly when it happens?"......or "has the front suspension suffered some sort of damage at some point, such that some joints are a bit loose somewhere (or that it caused a general misalignment)?"

May you find a quality suspension shop!

There's interesting YouTube videos where guys have mounted GoPro cameras under their 4x4's (with the lenses aimed at the front suspension) and then driven them (carefully!) under controlled circumstances (i.e., on a deserted street or parking lot somewhere) in order to duplicate their "death wobbles" and then evaluate the video later to see what exactly was happening. From the sound of your particular "death wobble," however, it occurs at pretty high/dangerous freeway speeds, so maybe not the best idea to try to evaluate the issue that way.
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Old 01-03-2017, 10:14 PM   #9
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Agreed, "death wobble" is solid front axle with worn out and damaged front end components. Generally bad track bar components allowing the axle to shift. If you're having some sort of serious wobble with a low mileage independent front suspension you've got real problems. Worn out bushings, ball joints, bearings, something is loose etc. get it checked out!
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Old 01-04-2017, 05:24 AM   #10
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Quote:
Originally Posted by rallypanam View Post
It's extraordinarily violent.
Sounds like a 'tank-slapper' on a motorcycle. How often does this occur?
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