Whine noise - bad turbo? bad belt tensioner? bad wheel bearing? What is it...???

[DavidinGA]

2021 GT2 Awd 37k miles now.

I've had this ongoing whine noise for a bit now and occasionally it's been louder than normal. The noise only happens when driving. I can not hear any noise when parked and reving the engine (lightly or all out).

The noise is not a whistle sound, it's definitely more like a supercharger whine. Sound increases by around 30mph and gets marginally louder as speed increases even when rpm's are very very low.

It seemed like the sound was louder during the cooler months, but now that it's warmer out I still hear it off and on.

I haven't had a chance to take a visual look inside the turbo's yet, but if they were bad shouldn't the sound manifest when the engine is under load even while in park?

If it is not the turbo is there a way to diagnose a bad belt tensioner or a bad wheel bearing?

Any other suggestions?

Thanks!

 

[DavidinGA]

I had someone suggest that it could be whine from the front differential. *if* it's the front dif and I were to disable AWD via the mod where I pull the fuse that makes my car rwd that should disable the front dif completely and if that's the issue the whine should stop, right?

 

[Thomby]

Does it do it under acceleration and decel/braking? What about coasting in neutral?

Does it change if you're cruising at steady speed and up/downshift (tied to rpm), or is it entirely tied to vehicle/wheel speed?

With a bad wheel bearing, you can sometimes hear the difference as you load or unload the tire, so for example leaning the car into a sweeping turn. Easier to do with the rears since you can brake to unload the inside rear, while accelerating hard enough to unload the front will be noisy.

 

[DavidinGA]

Does it do it under acceleration and decel/braking? What about coasting in neutral?

Does it change if you're cruising at steady speed and up/downshift (tied to rpm), or is it entirely tied to vehicle/wheel speed?

With a bad wheel bearing, you can sometimes hear the difference as you load or unload the tire, so for example leaning the car into a sweeping turn. Easier to do with the rears since you can brake to unload the inside rear, while accelerating hard enough to unload the front will be noisy.

The whine loudness increases as my speed increases. It is super faint until around 35mph or so. It seems to be tied to vehicle speed.

I just went for a quick drive. At 35mph I can most clearly hear the whine (less wind noise I suppose at that speed) and with constant throttle while keeping the rpms low/steady lifting off the gas does not drastically change the whine. The whine loudness grows a bit fainter as the vehicle coasts and slows down but no apparent drop in sound when I let off the gas.

I didn't think to try manually up/down shifting to see how that plays into things.

I tried to test for possible wheel bearing issues and I turned left and right while coasting and didn't hear any changes in the whine. I tried swerving a bit more aggressively left and right and still no change in whine, so perhaps it's not a wheel bearing.

I'm guessing it is not turbo-related as I'm not at all in boost when it starts to whine.

Must be engine/drivetrain related. Might it still be belt or tensioner-related?

 

[Thomby]

The whine loudness increases as my speed increases. It is super faint until around 35mph or so. It seems to be tied to vehicle speed.

I just went for a quick drive. At 35mph I can most clearly hear the whine (less wind noise I suppose at that speed) and with constant throttle while keeping the rpms low/steady lifting off the gas does not drastically change the whine. The whine loudness grows a bit fainter as the vehicle coasts and slows down but no apparent drop in sound when I let off the gas.

I didn't think to try manually up/down shifting to see how that plays into things.

I tried to test for possible wheel bearing issues and I turned left and right while coasting and didn't hear any changes in the whine. I tried swerving a bit more aggressively left and right and still no change in whine, so perhaps it's not a wheel bearing.

I'm guessing it is not turbo-related as I'm not at all in boost when it starts to whine.

Must be engine/drivetrain related. Might it still be belt or tensioner-related?

If it's tied to vehicle speed rather than engine speed it's probably not belts. How about putting it into neutral at 45-50 and coasting down to 30 with the engine at idle?

 

[DavidinGA]

If it's tied to vehicle speed rather than engine speed it's probably not belts. How about putting it into neutral at 45-50 and coasting down to 30 with the engine at idle?

I'll have to try that.

Thoughts on the potentiality of disabling awd via pulling the fuse to see if it disables the front differential to see if that's the issue?

 

[Thomby]

I'll have to try that.

Thoughts on the potentiality of disabling awd via pulling the fuse to see if it disables the front differential to see if that's the issue?

I think that'll just keep the transfer case clutches from engaging, but the half shafts and front driveshaft/transfer case output will still be spinning (since the front tires are moving), so I'm not sure that'll help.

I guess you could put all four tires up and drive it that way...

 

[oddball]

Right, pulling the fuse won't help - the diff can't be bypassed. The front driveshaft and axle shafts turn all the time. You need someone that can identify the noise.
First thing is a visual check. Are the boots on the CV axles still in good shape? Any obvious leaks? Any unusual noises when rotating the front or rear wheels?

 

[DavidinGA]

I think that'll just keep the transfer case clutches from engaging, but the half shafts and front driveshaft/transfer case output will still be spinning (since the front tires are moving), so I'm not sure that'll help.

I guess you could put all four tires up and drive it that way...

I tried pulling thbe fuse and sound remained.

I did waste a bunch rubber though, thx for that lol

 

[DavidinGA]

Right, pulling the fuse won't help - the diff can't be bypassed. The front driveshaft and axle shafts turn all the time. You need someone that can identify the noise.
First thing is a visual check. Are the boots on the CV axles still in good shape? Any obvious leaks? Any unusual noises when rotating the front or rear wheels?

Everything to me appears fine visually.

 

[mirza7789]

Everything to me appears fine visually.

Have you figured this out OP?

 

[G-533313]

Have you figured this out OP?

Ya.

It was a bad front diff. Took my Jb4 off and got it replaced under warranty.

 

[DavidinGA]

Have you figured this out OP?

Ya. It was a bad front dif.

I took my jb4 off and had it replaced under warranty and no more whine.