2018 CX-5 GT Transmission Replaced - High pitched whine

[HaydenM]

Figured it would be a good idea to document this on a forum in case others have the same issue.

We bought a 2018 CX-5 GT with about 35,000kms on the clock just under 11 months ago.

Right off the jump my wife told me that the car has a high pitched electronic-sounding whine on the highway. To tell you the truth I just told her not to worry about it, it’s a near brand new car with full warranty and extended warranty. My 2016 VW GTI also has a high pitched whine and it’s been to the dealer too many times without resolution.

Anyways, the symptoms were a high pitched electronic whine between 90kmh and 120h. With the windows up, air off and radio off you can hear it clear as day - Streamable Video and Streamable Video. I found this TSB - https://static.nhtsa.gov/odi/tsbs/2019/MC-10155437-0001.pdf and checked the car into the dealership mentioning the symptoms and this TSB.

I don’t think anybody will be surprised to read the dealership told me nothing is wrong. They gave me some BS saying this TSB doesn’t exist and my car isn’t listed anyways (2018 CX5 GT is listed and my VIN is within the range). Called Mazda Canada and they gave me the Canadian TSB # as that was a US market number.

Long story short they argued with me saying there was no noise and that they’ve only replaced 2 transmissions in 5+ years there and it’s highly unlikely I have an issue. Blames tire noise and wind noise from the window visors, typical dealership bulls*** - imgur.com.

The car was due for a recall of the fuel pump so I asked them to take one more listen to the car once it’s in the shop for that recall. Asked them to put it to speed on a hoist and stethoscope the transmission. Low and behold they called me yesterday to confirm they now hear the noise and a new transmission has been ordered.

Great. I am happy. Just of course frustrated it always takes a massive argument with dealerships to get anything done. They’re so quick to dismiss any concerns you have and get you out the door. Not to mention needing a brand new transmission with only 44,000 KM on the clock is definitely discouraging, bought this car for a future family vehicle to keep for years.. oh well.. fingers crossed.

Hopefully this helps anybody diagnosing a high pitched whine noise.

 

[erhayes]

There is a TSB for a high-pitched noise in the AT. Was caused by a noisy bearing I seem to remember. Not sure about which years. Ed

 

[HaydenM]

There is a TSB for a high-pitched noise in the AT. Was caused by a noisy bearing I seem to remember. Not sure about which years. Ed

Yes I linked that in my post lol

 

[yrwei52]

Yes I linked that in my post lol

Actually this's the 7th revision on the same TSB for the same transmission whining noise due to front input bearing failure since 2014. Each time the TSB says "This is caused by a damaged bearing in the transaxle due to improper configuration of the transaxle case. A modification has now been implemented on automatic transaxles with the following serial numbers:". I saw the same TSB back in 2015 when I made the decision to purchase my 2016 CX-5 new, I thought the problem has been fixed. Apparently it isn't after 6 tries by Mazda! I hope the 7th try in 2019 has truly fixed the problem, but not on my 2016 transmission.

 

[truthhurts]

Actually this's the 7th revision on the same TSB for the same transmission whining noise due to front input bearing failure since 2014. Each time the TSB says "This is caused by a damaged bearing in the transaxle due to improper configuration of the transaxle case. A modification has now been implemented on automatic transaxles with the following serial numbers:". I saw the same TSB back in 2015 when I made the decision to purchase my 2016 CX-5 new, I thought the problem has been fixed. Apparently it isn't after 6 tries by Mazda! I hope the 7th try in 2019 has truly fixed the problem, but not on my 2016 transmission.

Resurrecting an old thread here but did you say your 2016 had it? Did you get it replaced or just keep driving. I have a 2017 i just bought for what i thought was a steal. 106000 miles. Has the noise but really only noticable in 3rd which is strange. Sounds like alternator feedback through speakers in an old car. Wonder how many just kept driving on it and if it ever caused damage....

 

[postmortem]

Resurrecting an old thread here but did you say your 2016 had it? Did you get it replaced or just keep driving. I have a 2017 i just bought for what i thought was a steal. 106000 miles. Has the noise but really only noticable in 3rd which is strange. Sounds like alternator feedback through speakers in an old car. Wonder how many just kept driving on it and if it ever caused damage....

I'm having the same noise on my 2017 CX-5, 109k miles. I can still hear it while the vehicle is in parking. I think I can hear it more behind the left front wheel. Did you manage to solve this?

 

[truthhurts]

I'm having the same noise on my 2017 CX-5, 109k miles. I can still hear it while the vehicle is in parking. I think I can hear it more behind the left front wheel. Did you manage to solve this?

I did not. I was going to take in to the dealership to diagnose. Only then would mazda consider helping with cost of a replacement if thats what it is. Mine doesn't make the sound at highway speeds which the tsb states it should though atleast not loud enough to hear. It's really only noticable in mostly 3rd and less so in 5th. Im just going to drive it till it goes out and maybe ill put another in. It hasn't gotten any worse and ive been monitoring the fluid for metallic particles with a magnetic drain plug. There's a video on YouTube of a trans guy taking one apart and pointing out the affected bearing.

Also here is reddit thread with someones that makes the same sound how mine does. Reddit - The heart of the internet

 

[Lazy2.5]

Typical dealer nonsense.

Here's my experience with a local dealer, due to a recall for defective brake calipers:

L

Thread 'Mazda Dealership - Warranty Recall Work Results in a Brake Fluid Leak'

Aug 3, 2025

I brought my 2015 Mazda 6 to a local Mazda Dealership for Safety Recall 1217F - corrosion within the parking brake mechanism causing the rear brake calipers to seize, and reducing parking brake engagement efficacy. The overall experience was not just disappointing - it created a serious safety hazard.

Upon dropping off the car, I expressed my concern about an active brake rub. The service desk and mechanic disregarded this, claiming the vehicle was 'fine to drive' with what turned out to be severely seized rear calipers. They also claimed my calipers were not original, a questionable...

• Lazy2.5
• Replies: 6
• Forum: Mazda6 Forum

• 

It's not over yet. Make sure they do the replacement correctly and that the "new" transmission doesn't have any issues.

These Skyactiv 6 speed auto's are incredibly long lasting. I know of a 2016 Mazda 6 example with over 700,000KM on the original AT, and it has never been serviced as far as I know.

 

[postmortem]

I did not. I was going to take in to the dealership to diagnose. Only then would mazda consider helping with cost of a replacement if thats what it is. Mine doesn't make the sound at highway speeds which the tsb states it should though atleast not loud enough to hear. It's really only noticable in mostly 3rd and less so in 5th. Im just going to drive it till it goes out and maybe ill put another in. It hasn't gotten any worse and ive been monitoring the fluid for metallic particles with a magnetic drain plug. There's a video on YouTube of a trans guy taking one apart and pointing out the affected bearing.

Also here is reddit thread with someones that makes the same sound how mine does. Reddit - The heart of the internet

here is a video with my noise: Whistle noise after warm up


Does it sounds anything like yours? i recorded this while the vehicle was parked.

 

[postmortem]

I did not. I was going to take in to the dealership to diagnose. Only then would mazda consider helping with cost of a replacement if thats what it is. Mine doesn't make the sound at highway speeds which the tsb states it should though atleast not loud enough to hear. It's really only noticable in mostly 3rd and less so in 5th. Im just going to drive it till it goes out and maybe ill put another in. It hasn't gotten any worse and ive been monitoring the fluid for metallic particles with a magnetic drain plug. There's a video on YouTube of a trans guy taking one apart and pointing out the affected bearing.

Also here is reddit thread with someones that makes the same sound how mine does. Reddit - The heart of the internet

Update: just noticed that the whistle noise goes away if I put the car in D or R. If it's on P or N the whistle comes back and stays constant, increasing pitch if I rev it.

In D or R the noise comes back when I accelerate.

 

[truthhurts]

Update: just noticed that the whistle noise goes away if I put the car in D or R. If it's on P or N the whistle comes back and stays constant, increasing pitch if I rev it.

In D or R the noise comes back when I accelerate.

That's the same thing mine does. Does yours happen to have a different lugging noise around 2,700 RPMs when going up hill?

 

[postmortem]

That's the same thing mine does. Does yours happen to have a different lugging noise around 2,700 RPMs when going up hill?

I will have to test that. I can definitely hear the whistle behind the left front wheel, I tried the right one and I couldn't notice it. Also, just out of curiosity, I tried to diagnose the issue with chat gpt lol. Basically it narrowed it down to a vacuum/intake leak because the transmission is not under load when the vehicle is in park or neutral. So it making the noise while parked shouldn't be the transmission. Here is some of what it said:

Noise present in P/N (idling, no load) → Suggests it’s related to engine vacuum or an accessory spinning regardless of load.

Noise changes pitch with revs → Classic for a vacuum leak or intake resonance (less so for bearings, which usually growl/grind).

Noise disappears in D/R at idle (with brake on) → When you drop into gear, engine RPM dips and manifold vacuum changes. If the leak only whistles under higher vacuum (like in P/N idle), that explains why it goes quiet in gear until you accelerate.

Noise comes back during acceleration in D/R → As RPM rises, airflow/vacuum dynamics return, and the whistle reappears.


What this strongly suggests

A vacuum/intake leak that’s sensitive to manifold vacuum level.
Most likely culprits:

1. Brake booster vacuum hose / check valve (especially since it’s load-dependent).


2. PCV hose or grommet (cracks can whistle at high vacuum, quiet at low).


3. Intake manifold gasket (sometimes seals differently under varying load).



Why not alternator/pulley?

If it were an alternator bearing or idler pulley, the noise wouldn’t just vanish in D or R — those components spin regardless of gear.

 

[truthhurts]

I will have to test that. I can definitely hear the whistle behind the left front wheel, I tried the right one and I couldn't notice it. Also, just out of curiosity, I tried to diagnose the issue with chat gpt lol. Basically it narrowed it down to a vacuum/intake leak because the transmission is not under load when the vehicle is in park or neutral. So it making the noise while parked shouldn't be the transmission. Here is some of what it said:

Noise present in P/N (idling, no load) → Suggests it’s related to engine vacuum or an accessory spinning regardless of load.

Noise changes pitch with revs → Classic for a vacuum leak or intake resonance (less so for bearings, which usually growl/grind).

Noise disappears in D/R at idle (with brake on) → When you drop into gear, engine RPM dips and manifold vacuum changes. If the leak only whistles under higher vacuum (like in P/N idle), that explains why it goes quiet in gear until you accelerate.

Noise comes back during acceleration in D/R → As RPM rises, airflow/vacuum dynamics return, and the whistle reappears.


What this strongly suggests

A vacuum/intake leak that’s sensitive to manifold vacuum level.
Most likely culprits:

1. Brake booster vacuum hose / check valve (especially since it’s load-dependent).


2. PCV hose or grommet (cracks can whistle at high vacuum, quiet at low).


3. Intake manifold gasket (sometimes seals differently under varying load).



Why not alternator/pulley?

If it were an alternator bearing or idler pulley, the noise wouldn’t just vanish in D or R — those components spin regardless of gear.

My noise in park or neutral is much more subtle than when it's in 3rd and 5th gear. As soon as mine shifts into third it makes a rather high-pitched Whine. Still not super noticeable though if the radio is on a low to medium setting or if ac is on high.

 

[postmortem]

My noise in park or neutral is much more subtle than when it's in 3rd and 5th gear. As soon as mine shifts into third it makes a rather high-pitched Whine. Still not super noticeable though if the radio is on a low to medium setting or if ac is on high.

Same thing here. The weird part is that as soon as it goes into D or R the noise goes silent, until I accelerate and reach certain speeds.

 

[truthhurts]

Same thing here. The weird part is that as soon as it goes into D or R the noise goes silent, until I accelerate and reach certain speeds.

It's very peculiar and I've spent a lot of time researching it. I gave up. Maybe torque converter noise or another bearing. I've yet to have any signs of metal in my fluid. I've just learned to ignore it and hopefully nothing ever comes of it

 

[postmortem]

It's very peculiar and I've spent a lot of time researching it. I gave up. Maybe torque converter noise or another bearing. I've yet to have any signs of metal in my fluid. I've just learned to ignore it and hopefully nothing ever comes of it

I'm in the same boat, the vehicle is performing perfectly, it's just that noise that worries me. And I just got it too. I have a 3 months warranty that I bought with it. Maybe I can take it to a mazda dealer and they can tell me if there's something wrong with it.

 

[truthhurts]

I'm in the same boat, the vehicle is performing perfectly, it's just that noise that worries me. And I just got it too. I have a 3 months warranty that I bought with it. Maybe I can take it to a mazda dealer and they can tell me if there's something wrong with it.

Oh yeah if you have a warranty for sure I would take it in ASAP. I bought mine about 5 months ago with 103,000 miles on it from a older couple. I'm at 120,000 now. I honestly didn't notice it when I bought it until I drove it a few days later. I only paid 11,000 for it. They were about to trade it in. They seemed honest and said they never noticed it. Who knows. I had a feeling Mazda was not going to pay any more than half for a new transmission at the dealership. That's if they even agreed to it or if they even diagnosed it as a bad transmission. Wasn't worth my time. If it does go out I'll consider putting a used transmission in it or selling it as is and upgrading. The reason I wanted 2017 was to avoid cylinder deactivation. Would have to get a 2024 or 2025 to avoid it at this point.

 

[postmortem]

Oh yeah if you have a warranty for sure I would take it in ASAP. I bought mine about 5 months ago with 103,000 miles on it from a older couple. I'm at 120,000 now. I honestly didn't notice it when I bought it until I drove it a few days later. I only paid 11,000 for it. They were about to trade it in. They seemed honest and said they never noticed it. Who knows. I had a feeling Mazda was not going to pay any more than half for a new transmission at the dealership. That's if they even agreed to it or if they even diagnosed it as a bad transmission. Wasn't worth my time. If it does go out I'll consider putting a used transmission in it or selling it as is and upgrading. The reason I wanted 2017 was to avoid cylinder deactivation. Would have to get a 2024 or 2025 to avoid it at this point.

Same here, I wanted to avoid cylinder deactivation. I bought it from an used cars dealer (not a Mazda one) and I purchased a 3 months warranty separately that covers repairs in shops that accept it. Maybe I can take it to mazda, they can tell me what's wrong with it, and if they won't cover the repairs (which probably will be the case) I can take it to a ship that accepts the warranty.

 

[truthhurts]

Same here, I wanted to avoid cylinder deactivation. I bought it from an used cars dealer (not a Mazda one) and I purchased a 3 months warranty separately that covers repairs in shops that accept it. Maybe I can take it to mazda, they can tell me what's wrong with it, and if they won't cover the repairs (which probably will be the case) I can take it to a ship that accepts the warranty.

Yeah I would definitely take it to a shop that specializes in Mazda or the dealership. Take a copy of the TSB.

 

[postmortem]

Yeah I would definitely take it to a shop that specializes in Mazda or the dealership. Take a copy of the TSB.

Will definitely do! Will update if anything comes up. Thanks for the help mate.