Side to side "windy" swaying coming from the rear on high speeds

[Mikethe1]

Hi,

At high speeds after steering lane change etc. (but always occurs) it feels like something changes positions and truck starts swaying side to side and IMHO feels like coming from the rear. Then almost like that something "came back into place" and normal again.

What I already did:
1. New front upper control arms.
2. All wheels alignment.
3. All tires balancing.
Note - No noises whatsoever, no vibrations from the wheels/steering wheel.

Also went through this: Swaying at high speeds
he describes similar problem symptoms, they suggest rear wheel bearings - but those have typical sound & loose connection which I don't have.

My question: Where would you advise to look for a problem in the sense of the most probable/popular issue generally & with our 4th Gens...

Thanks in advance,

 

[Rick]

No mention of the condition of your shock absorbers. That could definitely be part of the issue. I would also check control arm bushings in the rear suspension.

 

[94Eddie]

Crawl underneath and look for obvious damage. Jack up rear and check for play in the wheels, bearing noise on rotation. Look for leaking rear struts or excessive bouncing. Is there excessive rust damage? Check sway bar end links and bushings.

 

[Mikethe1]

Hi,

Thanks y'all for the advices. So:
1. No leaking rear struts.
2. Obvious damage: haven't spotted anything.
Now, 18 years old 190K miles: Obviously if meticulously judging, so (almost all) bushings are not 100% in perfect condition. And that's the point: Practically I'm not going into a full scale replacement project.
The side to side swaying indeed happens every 1 minute for couple of seconds at high speeds, I can tell IMHO it definitely feels like side to side and not up & down bouncing (hence I don't think it's a strut/suspension) issue. When truck was loaded with 4 pax, the effect was restrained.
So I'm pretty sure among those 18 years old 190K miles imperfect bushings/whatever, there is the single one standing out in a total failure condition.
My question is whether based on the addition of "The side to side swaying indeed happens every 1 minute for couple of seconds at high speeds, I can tell IMHO it definitely feels like side to side and not up & down bouncing (hence I don't think it's a strut/suspension) issue. When truck was loaded with 4 pax, the effect was restrained", there might be some immediate suspect?
I tried lifting, playing with the wheel, assessing loose/free play, removing the wheel, touching the bushing, trying to move parts to engage some movement etc. but I couldn't spot based on them if something is wrong. So some focus where/how to look for might help me here.

Thanks in advance,

 

[rmeline]

As 94Eddie mentioned, inspect the sway bar link bushings. When I drove my brother's stock 4th gen Explorer it swayed more than any street vehicle I've ever driven. The link bushings and some of the plastic spacers were shot. Spent $30 and an hour of work to install four new links. Big difference.
This may not be your ride's issue at all, but give your's a shake. If they rattle, tighten or replace. See screenshot.

 

[toypaseo]

I would also recommend looking at the endlinks.

I either broke, or a nut and bushing fell off, on one of my front ones on my 96. It was like driving a swaying boat on the interstate. Sway when changing lanes, and from any road irregularities.

 

[Mikethe1]

I went to a garage, they checked, said front sway bar bushing are the issue, replaced - 0 results - the problem is not there.

 

[94Eddie]

Did they check the rear end links and bushings and all four struts?

 

[Mikethe1]

Yes, and I also see that "rear end links and bushings and all four struts" visually look fine - not damaged like the front sway bar bushings above.
Anyway, does symptoms logically look like rear end links issue?

 

[94Eddie]

Yes, and I also see that "rear end links and bushings and all four struts" visually look fine - not damaged like the front sway bar bushings above.
Anyway, does symptoms logically looks like rear end links issue?

Struts can be bad and visually look fine. When I had about 140k miles on my Mountaineer I decided to install four new struts. I didn't think there was a lot wrong with the originals (no visual leaks) but there was a little more bounce and sway than I wanted. I bought this vehicle with around 100k miles on it so I had no reference point as to how new struts behaved. The first drive with the new struts installed was an eye opener and showed me just how much the old struts had worn over the miles. There was far less bounce and handling improved quite a bit. I had no regrets with the decision to replace all four struts. After that the front and rear end links were replaced which compounded on the improvements of the new struts. Soon I will be replacing the front and rear sway bar bushings. If you are still on the original struts at 190k miles then they are very likely causing some drivability issues. Also, I can see where a substantially weaker strut on one side can cause the issue you are seeing. If this is the case then replace both sides where the weak shock is located. Replacing all four is probably justified if it is financially viable.

 

[Mikethe1]

Thanks for the detailed explanation.
It feels like there is a single significant issue causing distinctive (very harsh) side to side swaying on high speeds, that kicks in for couple of seconds every minute or so.
This is why I don't think it's a case for compounded improvements from replacing more 190K miles parts (of course ideally I would swap there everything): Also the front sway bar bushings, even though old ones were complete garbage - I don't really feel the difference now (factoring out the main swaying issue feeling).
Another description for how the side to side sway feels: It's like in addition to the general side to side movement of the entire car, each wheel (side) spins in and out periodically. Like (single wheel/side) sliding out, then back, then out again kind of in rhythmic pattern.

 

[94Eddie]

You might be in a situation where firing the parts canon is your only option. A weak strut combined with gusts of wind, turbulence from passing vehicles, etc. could be the source of your problem. Did this problem come on quickly or over a period of time?

 

[07EddyB]

Struts can be bad and visually look fine. When I had about 140k miles on my Mountaineer I decided to install four new struts. I didn't think there was a lot wrong with the originals (no visual leaks) but there was a little more bounce and sway than I wanted. I bought this vehicle with around 100k miles on it so I had no reference point as to how new struts behaved. The first drive with the new struts installed was an eye opener and showed me just how much the old struts had worn over the miles.

Thanks for the detailed explanation.
It feels like there is a single significant issue causing distinctive (very harsh) side to side swaying on high speeds, that kicks in for couple of seconds every minute or so.
This is why I don't think it's a case for compounded improvements from replacing more 190K miles parts (of course ideally I would swap there everything): Also the front sway bar bushings, even though old ones were complete garbage - I don't really feel the difference now (factoring out the main swaying issue feeling).
Another description for how the side to side sway feels: It's like in addition to the general side to side movement of the entire car, each wheel (side) spins in and out periodically. Like (single wheel/side) sliding out, then back, then out again kind of in rhythmic pattern.

Listen to 94Eddie - I also replaced all my struts at around 130K and the Explorer tightened up considerably. No visual indication that they were bad - just an overall loose feeling while driving that drove me to do it. It drives like new now.
Struts just don't last to 190K miles on a heavier vehicle.
If you think about it there really isn't anything on your suspension that would cause what you are saying in a rhythmic pattern. It's either happening every second or two or constantly at speed or happening due to outside influences. Outside influences would be the road, the wind, etc. I can't think of anything that would cause an issue for 'just a couple of seconds every minute or so' unless it's an outside influence.

So I would put my money in new struts. You're basically just running on the springs right now.

 

[toypaseo]

Something else to look at… tires.

The 96 I just bought, had old cracked bald cheepo deluxe tires on it. I bought shocks thinking they are pry shot. I put my summer wheels and tires on it from my other 96, and just that made a huge difference…

 

[Mikethe1]

So the answer - Rear wheel bearing.
It was completely worn out, therefore no typical "grinding" faulty wheel bearing noise.