Whirring noise when slowing down - anyone had this?

[D.J.]

Electronic power steering coupling

But @Dream_Merchant said it happens when going straight.
What coupling could cause the whirring noise while decelerating in a straight line.
The RMPS has only one coupling.

It's been both while going straight and turning - but always decelerating that we've heard so far.

 

[Nocostinger]

My 2020 GT AWD has that on deceleration when its under 20 degrees out.

 

[G-974529]

What happened next!

 

[Thomby]

Is it kind of a like a plastic fan rubbing against something, or like trilling your tongue against the roof of your mouth? Off-throttle, coasting down from around 2000 to 1000 rpm, and touching the throttle makes it immediately go away?

If so it may be wastegate rattle, also common on some BMW, VW, and Ford EcoBoost models. A light spring on the wastegate linkage to take out the slack will mute it.

T

Post in thread 'Tapping/rotating noise just under 2000 rpms'

Dec 15, 2024

https://imgur.com/a/0KYp50r

Brought it to dealer they said they “couldn’t replicate noise” any help? Think my dealer is lying to me honestly. Attached the video in link above

If you coast down from say 40mph to 20mph, off the throttle, so the engine is just going from 1500-2000 rpm down to 1000, do you hear it then? I get what sounds like a faint version of this, almost like trilling your tongue against the roof of your mouth.

It stops when revs dip to around 1000 rpm, or with any touch of the throttle, and is quiet enough it's proven difficult to capture on video. Below are two clips I...

• Thomby

 

[rbf351]

seems like I have the same issue on my 22 AWD GT2.

Initially thought it was the wheel bearing, but had an issue getting one of the ball joints out yesterday, so didn't get to replace the bearing.

Instead I pulled the AWD fuse which stops the front differential from working.

Now there is no more noise.

I have to now see if it needs fluid or if the differential is bad

 

[D.J.]

seems like I have the same issue on my 22 AWD GT2.

Initially thought it was the wheel bearing, but had an issue getting one of the ball joints out yesterday, so didn't get to replace the bearing.

Instead I pulled the AWD fuse which stops the front differential from working.

Now there is no more noise.

I have to now see if it needs fluid or if the differential is bad

Pulling that fuse disables your transfer case clutch - so your noise is potentially related to the transfer case and clutch pack.

 

[rbf351]

Pulling that fuse disables your transfer case clutch - so your noise is potentially related to the transfer case and clutch pack.

it also stops the front differential from working other than in a neutral position. so there is no power from the transfer case being put to it

 

[Thomby]

it also stops the front differential from working other than in a neutral position. so there is no power from the transfer case being put to it

I think all the same parts will be moving (wheels --> half shafts --> spider gears --> driveshaft from transfer case), just driven by the wheels 100% of the time instead of transmitting torque downstream as the clutches engage.

And if it's only happening under deceleration, there's no torque coming from the engine side. But I'm not sure if the transfer case will disengage the clutches under decel or leave them partially engaged to share the engine braking with the rear wheels. @D.J. probably has logs that answer that.

Have you tried replicating the issue in Eco, Comfort, and Sport since the clutch pack should be engaging to different degrees across the drive modes?

 

[rbf351]

I think all the same parts will be moving (wheels --> half shafts --> spider gears --> driveshaft from transfer case), just driven by the wheels 100% of the time instead of transmitting torque downstream as the clutches engage.

And if it's only happening under deceleration, there's no torque coming from the engine side. But I'm not sure if the transfer case will disengage the clutches under decel or leave them partially engaged to share the engine braking with the rear wheels. @D.J. probably has logs that answer that.

Have you tried replicating the issue in Eco, Comfort, and Sport since the clutch pack should be engaging to different degrees across the drive modes?

Tried all different modes, and so far removing the fuse is the only thing that stopped the noise.

seems like when you are slowing down at a fast rate the car might be putting some torque into the front differential for engine braking like it does with the rear

 

[rbf351]

the is the best I was able to capture the noise

 

[D.J.]

the is the best I was able to capture the noise

And if you pull the AWD fuse, the noise is completely eliminated?

 

[rbf351]

And if you pull the AWD fuse, the noise is completely eliminated?

it seemed like it did the other day, but I only took a 2 minute drive

I will find out for sure later today as I'm driving 45 miles with the fuse out, and lots of stop and go traffic

 

[Thomby]

the is the best I was able to capture the noise

That is a much deeper sound than the whirring sound I was thinking of, and my initial guess would've been a front wheel bearing, but if it's tied to the AWD clutch pack's engagement under decel, I wonder if it's a bearing on the transfer case's output shaft (complaining under load but not when freewheeling).

One way to test this would be to replace the fuse so the clutches activate, and remove the mechanical linkage between the transfer case and wheels, but I doubt there's an easy way to remove either the transfer case output shaft or half shafts (and if you did the transfer case may just dump all its fluid).

I guess you could put the car up on jackstands or a lift and rotate the front wheels to check for slack or knocking between them and the transfer case (but again, it may not be apparent with no load).

 

[rbf351]

That is a much deeper sound than the whirring sound I was thinking of, and my initial guess would've been a front wheel bearing, but if it's tied to the AWD clutch pack's engagement under decel, I wonder if it's a bearing on the transfer case's output shaft (complaining under load but not when freewheeling).

One way to test this would be to replace the fuse so the clutches activate, and remove the mechanical linkage between the transfer case and wheels, but I doubt there's an easy way to remove either the transfer case output shaft or half shafts (and if you did the transfer case may just dump all its fluid).

I guess you could put the car up on jackstands or a lift and rotate the front wheels to check for slack or knocking between them and the transfer case (but again, it may not be apparent with no load).

Unfortunately removing the fuse did nothing, and the noise is still there. It takes a little bit of driving around for it to happen.

As long as it's not below freezing, and there is no rain or snow I am going to change the wheel bearing this weekend.

 

[Thomby]

Unfortunately removing the fuse did nothing, and the noise is still there. It takes a little bit of driving around for it to happen.
As long as it's not below freezing, and there is no rain or snow I am going to change the wheel bearing this weekend.

Is it specific to a side? Before you go parts swapping, it may be worth finding a nice long curve where you can pitch the weight onto one side and then the other while decelerating, and see if that reveals anything.

You may also want to see if it'll happen both decelerating via the brakes and engine braking, and with the engine in gear vs. neutral, to further narrow things down.

 

[rbf351]

Is it specific to a side? Before you go parts swapping, it may be worth finding a nice long curve where you can pitch the weight onto one side and then the other while decelerating, and see if that reveals anything.

You may also want to see if it'll happen both decelerating via the brakes and engine braking, and with the engine in gear vs. neutral, to further narrow things down.

I first noticed it while taking some turns, but hasn't done that lately

tried that yesterday as well, happens while in neutral or in drive, also doesn't matter which mode or which gear

 

[Thomby]

I first noticed it while taking some turns, but hasn't done that lately
tried that yesterday as well, happens while in neutral or in drive, also doesn't matter which mode or which gear

More noticeable on one side? Under braking or decel (does it happen even if you aren't using the brakes?) regardless of the car being in gear would point to a front bearing, but it's less likely that both are failing together.

 

[rbf351]

More noticeable on one side? Under braking or decel (does it happen even if you aren't using the brakes?) regardless of the car being in gear would point to a front bearing, but it's less likely that both are failing together.

sounds as if it's coming from the right side, and was only on one side when turning, now it's only happening while braking. no noise at all if just letting the car slow down on it's own.

 

[Thomby]

sounds as if it's coming from the right side, and was only on one side when turning, now it's only happening while braking. no noise at all if just letting the car slow down on it's own.

Maybe locked caliper/dragging pads? Probably want to get the front right up and spin the wheel back and forth by hand. You may also want to check the right rear as well, but you'll need to use the shift override to get it into neutral and release the parking brake (you may already know all this, but extra wheel chocks).

 

[rbf351]

Maybe locked caliper/dragging pads? Probably want to get the front right up and spin the wheel back and forth by hand. You may also want to check the right rear as well, but you'll need to use the shift override to get it into neutral and release the parking brake (you may already know all this, but extra wheel chocks).

that was the first thing that was checked, even replaced rotors and pads in December.

that's why I'm going with the bearing at this point