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Discussion Starter #1 (Edited)
Hello - New forum user.

I've tried the search function but haven't found much.

We've got a 2018 Acadia Denali with ~ 8500 miles on it. Recently, it's started 'whining' while decelerating from 40 to 35 mph , the whine is sometimes noticeable in the 20-30 mph range as well.

At first, this was only heard in AWD.

We took it in, and the service center ended up replacing the rear differential. Apparently they road tested it and said it was good to go.

We picked the vehicle up and the whine started again. This time, it's most noticeable in FWD, still between the same speeds.

One thing to note, it has been extremely cold recently (Midwest), however the whine was also present when temps were much more reasonable. 15+F .

Has anyone experience something like this ? Here is a video/(really just need the sound) of the issue: youtube.com/watch?v=tVbwwdp9MnM

I can't link directly, I think a copy/paste is needed.

The video is about a minute long, air temps were about 0. This drive was after letting the vehicle sit outside for an hour after picking it up from the dealer. In the vehicle, it gets extremely loud - almost sounds like their is an emergency vehicle approaching, I'm not sure how well this comes through on the cell phone video.

Thanks for any input you have.
 

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Your post count isn't high enough to post links (5 minimum). I did it for you.


:welcome: to the forum.
 

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Discussion Starter #3
Thank you!

I am planning on heading back to the dealer tomorrow with this video... I'd also like to ask them if we can hop in an acadia they have on their lot to see if it does the same thing..
 

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Discussion Starter #4
A couple more details I thought of:

The sound does tend to become quieter as the vehicle fluids warm up. It never goes away, but you have to be listening for it once things get warm.

When cold, the sound does persist if I pop the vehicle into neutral.
 

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I wouldn’t think a “delicate” sound like that would be coming from a major mechanical like the transmission, and even if it was - I’d doubt you’d be able to hear it that well inside the vehicle.

Also shocked that a dealership would replace a differential based on so little information. Maybe they really didn’t replace *anything*!

I’d keep searching in the engine compartment...
 

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I wouldn’t think a “delicate” sound like that would be coming from a major mechanical like the transmission, and even if it was - I’d doubt you’d be able to hear it that well inside the vehicle.

Also shocked that a dealership would replace a differential based on so little information. Maybe they really didn’t replace *anything*!

I’d keep searching in the engine compartment...
Is your vehicle an AWD model (can’t see your signature on my phone)? If so, there are threads here from owners hearing some kind of “droning” noise when switched to AWD mode (but quiet in FWD mode)...
 

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Discussion Starter #7 (Edited)
Is your vehicle an AWD model (can’t see your signature on my phone)? If so, there are threads here from owners hearing some kind of “droning” noise when switched to AWD mode (but quiet in FWD mode)...
It is an AWD model.

The sound occurs in both FWD and AWD, generally only in the 35-40mph speed range. Although when the vehicle is very cold, it is also audible in the 25-30mph range.

I'm going to let the dealer keep searching for the noise. In my mind they've already acknowledged that it's not a normal vehicle noise by replacing the rear diff. I'll keep pushing to have them fix it. (While being polite of course).

I believe the reason they replaced the rear diff is because when they had the vehicle on the lift and started spinning everything, it got very loud back there.

Obviously there is more going on.

I believe I found one of the threads discussing the droning noise in the 2017 Acadia. It appears that this noise is related to higher speeds. Our whine/drone is really only apparent between 35-40.

I'll test later this evening to see if I notice anything at higher speeds in AWD.

Thanks for your messages!
 

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Hi bcereus2,

I have a 2017 Acadia Denali AWD and currently at 41K miles.
I have recently started hearing this exact same noise during initial few minutes of morning commute when speeds are between 30 mph and 40 mph (like you mention too). Also I have observed noise is more noticeable when weather is cold. Once on freeway, I can't say clearly if noise goes away or it's just road noise masking it. Will try to see if I get same noise when in FWD mode too. Interestingly I am noticing this after significantly larger number of miles, compared to yours. I have been following all service/maintenance as per schedule.

Since I haven't changed my factory installed brake pads yet, wondering if noise could be related to that? Or some fancy feature which will try to warm-up/dry-up the brake pads during initial few minutes of use etc. I see there is already a thread '2018 Brake noise' , but not sure if both noise are same.

Wondering if any older Acadia models had this issue and it got resolved eventually, same could apply here.
 

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Discussion Starter #9
Thanks for the reply.

The vehicle has been back at the dealer for the past week, and they are currently replacing the drive shaft. (We were supposed to get it back last Thursday but the weather stopped their parts delivery).

I'm hoping this fixes the issue.

They did give us a 2019 Acadia Denali as a loaner and I couldn't get it to make the same noise, even when left outside in the cold.

I'll update this thread once we have the vehicle back.
 

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Discussion Starter #10
New drive shaft in - picked up the vehicle today, temps are in the mid 20's. I can still hear a faint whining noise in the same area that I've heard it before.

I'll be going back to the dealer tomorrow.

Anyone familiar with Lemon Laws?
 

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Discussion Starter #13
Thanks - from what I can find it looks like they get four tries in MN. Next time will be #3.. here's hoping they find a fix.
 

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I can jump in with the previous body style. I have a 2015 AWD and started hearing this exact same noise about 4 weeks ago. Similar conditions cause it for me. It’s always on a cold start, but only when the outside temps are really cold. The highest outside temp I’ve noticed it at was 26 degrees, going by the temp gauge on the radio. Anything above that and it doesn’t happen or at least I can’t hear it. We had one morning a couple weeks ago that was 1 degree and it took a while for the noise to lessen. Generally for me it tends to go away after the car has been driven for about 15 minutes. In my case it kicks in at 31mph and will be audible until 34mph while accelerating. If you let off the accelerator at 34mph and watch the speed slow down, I’ll hear the noise until it drops to 31mph, as soon as it slows to 30mph it’s quiet again. The other day I started the car at 42 degrees and couldn’t hear the noise.

The first time I heard the noise I thought it was coming through a speaker, almost like feedback as to me it sounded like an electronic sound. However I was unable to figure out where the noise was coming from. First thing I did was turn off the radio. It sounded like it was coming from the speaker of the rear passenger side door but after sitting back there with someone else driving I could determine that it wasn’t. When I put the windows down I don’t hear it outside the car, it seems like it is strictly inside, however it’s hard to be positive of that with road noise.

I had body work done on my car over the summer and I was starting to think it was something the body shop did. The only electrical part that was replaced was a headlight assembly but I didn’t know if a wire was pinched or something else they got their hands on that was causing this issue. But after seeing multiple people with the same noise it’s making me think it’s unrelated to the body work, unless the OP and second person with the same issue also had body work done, then that may point us in a direction since it seems like the OP’s dealership is not pinpointing the cause.

Having said that I have a maintenance appointment at my dealership next week. I will try to record the noise in my car and see if it sounds familiar to them, though I won’t be holding my breath.

And while mine is a 2015, it only has 12,500 miles on it. This is the 4th winter I’ve had the car and the first time I’ve ever heard this sound.
 

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Just another thought, does anyone know if some system in the Acadia starts to engage/disengage around that 31-34mph speed?
 

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Discussion Starter #16
Hi FDV101

I did have minor body work done shortly before noticing this sound.

We had the lower panels on the passenger side pulled off and repainted. (some jerk in a parking lot somewhere)

I don't think my noise is related to the body work - It could be, but I have my doubts. One of the biggest reasons I have doubts is due to the fact that when I put the vehicle in neutral, the sound goes away. As soon as I put it back in drive in that speed range it comes right back.
 

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bcereus2,
I also had my doubts about the body work, but for me that was the only thing that changed on the car from last year to this year, not counting parts that could just be failing so that’s why I had that thought. What I forgot about until I read your reply was that to correct a problem that the body shop caused while it was in their possession, they took off my driver’s side front door. I know there’s a bunch of wires that go into that door. I may be going down a road that makes no sense but just want to rule things out. When you had your lower panels repainted do you know if they pulled off any of the doors?
I also tried putting the car in neutral and if I remember correctly my noise stayed , until the speed decreased enough that it got to the “quiet zone”. I will try it again just to be sure but I don’t remember anything affecting it other than speed.
I’ll see if I can get a cold enough day and double check putting it in neutral and reply with the results.
Obviously I’ll also post anything that the dealership tells me. I have an extended warranty on this car so it will be he dealership doing any repairs, I just don’t want them ripping the car apart guessing at what they think the issue is.
I’m hoping it’s a really cold day when I go there, because if the car can cool down enough while it’s there I will see if a mechanic will take a ride with me and hope the noise is present.
I know you have a very good recording of the sound, but do you know if one of the mechanics heard the noise first hand if he drove your car?
 

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Discussion Starter #18
Thanks for getting back to me.

Yes the service tech has heard the noise when driving the car.

When it was in the first time they put it up on the lift, put power to the wheels, and it got loud at the rear differential, which is apparently what led them to replace that.

They did not pull off doors when they did my body work. Just the plastic panels down below the doors. I agree it is something to consider though, as the work was done only a couple of weeks before we started hearing the noise... however it was also above 30F.

To touch back on the neutral point - when it was extremely cold here (-15F) , the sound did stay when i pushed the vehicle into neutral, however now that it is a balmy 15-20F the sound definitely goes away when pushed into neutral and comes right back when put back into drive.
 

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We’re supposed to be around 18 to 20 degrees when I should be getting in the car tomorrow so I’m expecting it to make the sound and I should be able to test out the neutral situation again
 

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I have my Denali in stock condition. No body work at all. Hopefully that helps in ruling out body work causing this :)
Here in Northern California, we have temperatures around 37.4F when its cold ... and I hear this sound only for a while and then it seems to go away.
I usually have drive mode in AWD and today just to try out I put it in FWD (similar temps as when I hear sound) and I couldn't hear it. So that also makes me think if its something to do with rear axle gears/assembly/oil making this sound when cold. But I think OP also mentions he hears this sound in FWD.

Another point being, GMC recommends "Replace rear axle fluid. If equipped with positraction rear axle." in Maintainence schedule @45K miles. And my car is at 41K, could that have some relation to this sound, since until recently I never had heard it.



I have oil change appointment this week, will try to bring up this issue with them. But I think it will be very hard to reproduce this issue with the mechanic as car would have warmed-up enough by the time I reach there :(
 
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