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Discussion Starter · #1 · (Edited)
Hi Everyone,

My Acadia has started to rock side-to-side (left/right) at highway speeds (> 60 mph / 100 kph). It is a 2009 SLT1 (18" wheels) with 65,000 mi / 105,000 kms. Any ideas as to what could be the problem?

I took it to the dealership (and paid $99 for an inspection), but they found nothing. but the rocking is now getting worse. (As an unrelated aside, the dealership did, however, tell me my cabin air filter needed replacing, even though my model does not have one... Needless to say I was not pleased. But I won't be taking it to them again.)

Any advice you have is appreciated.

Thanks in advance,

Laurent
 

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First thing that comes to mind is a broken stabilizer link, or the bar itself is broken (the car has both front and rear stabilizers). I'm assuming this is happening on a road you're familiar with driving and can rule out pavement flaws.
 

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Discussion Starter · #3 ·
First thing that comes to mind is a broken stabilizer link, or the bar itself is broken. I'm assuming this is happening on a road you're familiar with driving and can rule out pavement flaws.
Thanks for the reply.

I too thought it might be the pavement at first. But after experiencing it on more than once occasion, I am pretty sure it is not the road, although I can never be certain. (I notice it most on the Trans-Canada highway, which passes through the middle of Montreal and -- in theory -- should be reasonably smooth.)

Here's a beginner's question: Can this be diagnosed without taking off the wheels?

Thanks again,

Laurent
 

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Here's a beginner's question: Can this be diagnosed without taking off the wheels?
Worn and broken suspension components can usually be visualized with the wheels on the car. Also, some diagnostic procedures require the wheels to be on the car to 'load' or 'unload' the suspension.
 

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Discussion Starter · #6 ·
My understand of what you are writing is that this "rocking" does not occur all of the time. Only some of the time. Right? Wrong? George
I would say that I only notice it at high speeds, on the highway (generally going straight).

Thank you,

Laurent
 

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Discussion Starter · #7 ·
So I took the Acadia to my old (non-GM) mechanic who found that one of the shock absorbers was shot (which GM did not manage to notice, even though I paid for an inspection of the suspension). I ended having both shocks and a tie rod replaced. However, I went on a road trip this weekend and the problem still persists. (I don't regret replacing the shocks, as it was clear that one of them was shot...)

My mechanic recommends I now do an alignment to see if that might remedy the problem. (I have to go elsewhere for that.) Does that make sense? I am not a mechanic, but I am not certain as to how a misalignment could cause a side-to-side (i.e. left-right) rocking? Their explanation was that the car could be alternately pulling in each direction...

Any opinions?

Thanks,

Laurent
 

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I'd question the experience of a mechanic who replaces a tie rod end without sending the car to an alignment center as part of the job. Read about toe-in and toe-out and see if the symptoms of an incorrect toe setting produces what you're feeling. There's a difference between "rocking side to side" and "pulling left and right." An improperly set toe can cause a pulling sensation (left, right, or both) when the road surface is uneven or not cambered (crowned) properly.
 

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"There's a difference between "rocking side to side" and "pulling left and right." An improperly set toe can cause a pulling sensation (left, right, or both) when the road surface is uneven or not cambered (crowned) properly."

You may have found a key here. To me "rocking" is the motion that occurs when somebody(or bodies) stand at the side of the vehicle and push on the top towards the opposite side.

George
 

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Discussion Starter · #10 ·
I'd question the experience of a mechanic who replaces a tie rod end without sending the car to an alignment center as part of the job. Read about toe-in and toe-out and see if the symptoms of an incorrect toe setting produces what you're feeling. There's a difference between "rocking side to side" and "pulling left and right." An improperly set toe can cause a pulling sensation (left, right, or both) when the road surface is uneven or not cambered (crowned) properly.
Thank you both, Speleos and GeorgeC.

I read up on toe, but it was not clear (to me, at least) if what was described was related to this rocking I am noticing.

In any case, I got an alignment at another GM dealership. The car still seems to rock. Moreover, I noticed that when driving at 65+ mph, if I give the steering wheel a quick little left-right shake (then back to center), the car will really rock left and right a second time (more intensely than it moved when I shook the steering wheel) .

Any ideas as to what i should have checked next? Could it be the tires? I just got new summer tires (Bridgestone Duellers) after the winter, and this only seems to be a recent issue...

Thanks again for your input, which I invariably appreciate. This site has helped me a lot since I have owned this car.

L
 

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... Any ideas as to what i should have checked next? Could it be the tires? I just got new summer tires (Bridgestone Duellers) after the winter, and this only seems to be a recent issue...
Tires would be suspect if all things mechanical check out on the car. They're the last link between the car and the road. Many reviews of those Bridgestones suggest their handling properties aren't real good. :shrug:
 

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Discussion Starter · #12 · (Edited)
So I was finally able to solve this problem. I just thought I would post the answer in case anyone else has the same problem, as well as to let those who kindly offered me advice know what it was.

I took it the same dealership who did the alignment. (I had not mentioned this issue to them at the time. I just asked them to do an alignment when they were replacing the AC evaporator -- concurrent problems with this Acadia. I am over $3K in repairs so far this year...) They suggested I take the mechanic out with me for a test drive. He thought it was coming from the back end, which seemed reasonable to me from the handling when it did this rocking back and forth). It turns out both rear toe links needed replacing. I am happy to say this has solved the problem...

After the repair, the dealership did the alignment again, and were kind enough to not charge me for it as I had just done one a week or so earlier in a attempt to resolve this problem. (They also gave me a good price on my evaporator repair, so I think I have found a new preferred dealership.)

Thanks again to those of you who helped me with this.

Laurent
 

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Glad to hear you got things worked out, @laurentbm. Thanks for posting the follow-up, too. Your report will be helpful to others who experience similar circumstances. Now, you can go out and enjoy the ride! :)
 

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So I was finally able to solve this problem. I just thought I would post the answer in case anyone else has the same problem, as well as to let those who kindly offered me advice know what it was.

I took it the same dealership who did the alignment. (I had not mentioned this issue to them at the time. I just asked them to do an alignment when they were replacing the AC evaporator -- concurrent problems with this Acadia. I am over $3K in repairs so far this year...) They suggested I take the mechanic out with me for a test drive. He thought it was coming from the back end, which seemed reasonable to me from the handling when it did this rocking back and forth). It turns out both rear toe links needed replacing. I am happy to say this has solved the problem...

After the repair, the dealership did the alignment again, and were kind enough to not charge me for it as I had just done one a week or so earlier in a attempt to resolve this problem. (They also gave me a good price on my evaporator repair, so I think I have found a new preferred dealership.)

Thanks again to those of you who helped me with this.

Laurent
Laurent,
I started having the same problem with my 2010 Acadia, at 147,000 miles, and it started the swaying/rocking at highway speed (55 mph or greater) two weeks after I replaced the struts (one was leaking) in Nov 2016. I've replaced the struts, shocks, rear complete arm assembly, new tires, alignment, sway bar bushings and arms (front and rear), with no change, after about $4000. My dealership couldn't find the problem either after 2 or 3 trips. I saw your post about this and showed it to my husband (my mechanic), but he doesn't know exactly what the "rear toe links" are. I've looked to order them, but that particular "rear toe links" does not show up by that name. Could you advise what is the correct terminology for these parts? I now have 182,000 miles on it, and have just learned to live with it, but I would love to be able to have it fixed.
 

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Thanks for the reply.

I too thought it might be the pavement at first. But after experiencing it on more than once occasion, I am pretty sure it is not the road, although I can never be certain. (I notice it most on the Trans-Canada highway, which passes through the middle of Montreal and -- in theory -- should be reasonably smooth.)

Here's a beginner's question: Can this be diagnosed without taking off the wheels?

Thanks again,

Laurent
If you're talking about the 40 through the West Island, that stretch will produce all sorts of weird sensations in cars. Tires feel out balance, suspension feels off, etc. I've noticed this in my Acadia, my Suzuki Grand Vitara and my Volt. No idea why, but the road is just weird, especially eastbound.

In your case, the weird road probably amplified the symptoms from your real problem.
 

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So I was finally able to solve this problem. I just thought I would post the answer in case anyone else has the same problem, as well as to let those who kindly offered me advice know what it was.

I took it the same dealership who did the alignment. (I had not mentioned this issue to them at the time. I just asked them to do an alignment when they were replacing the AC evaporator -- concurrent problems with this Acadia. I am over $3K in repairs so far this year...) They suggested I take the mechanic out with me for a test drive. He thought it was coming from the back end, which seemed reasonable to me from the handling when it did this rocking back and forth). It turns out both rear toe links needed replacing. I am happy to say this has solved the problem...

After the repair, the dealership did the alignment again, and were kind enough to not charge me for it as I had just done one a week or so earlier in a attempt to resolve this problem. (They also gave me a good price on my evaporator repair, so I think I have found a new preferred dealership.)

Thanks again to those of you who helped me with this.

Laurent
Thanks to the original poster and thanks to the forum for still having this thread online. I had the exact same problem as described on our 110k mile 2014 Acadia. Things got scary a couple of times on a 2000 mile road trip when the car jumped across the road by about 3 feet after hitting bumps on the highway. Once we got home I ordered and replaced the toe links and shocks, as detailed above, and it has completely fixed the issue. It's like a different car to drive now.
Thanks again for posting your final update (y)(y)
 
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