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Discussion Starter #1 (Edited)
Compiled from various GM-Volt threads. The questions below are answered in a numbered section lower on the post.

  1. I have started to notice a sound progressively getting louder when I brake and Accelerate but mostly very loud when I am stopping. It sounds like a table saw winding down. This is something that never happened before. What is causing this?
  2. What kind of damage can I cause by driving the car with this issue?
  3. Do I need to have the car towed to the dealer?
  4. Is there a service bulletin I can refer my Chevy dealer to? Yes, PIP5081H
  5. What tools are needed by the dealer for the repair?
  6. How difficult is the bearing repair?
  7. Does the repair require removing the transmission?
  8. Does the rotor need to be replaced in addition to the bearing cage?
  9. Does the entire MG-B rotor/stator assembly need replacing?
  10. Once repaired, can the bearing fail again?
  11. What if the bearing noise problem persists or returns after repair?
  12. What causes the bearing to fail?
  13. Is failure of the bearing related to driving in Low? Number of miles? The car year?
  14. Is failure of the bearing common?
  15. If this bearing failure happens outside the warranty, will it be expensive?
  16. How is the whining or table saw noise being created?
  17. Why is the whining sound louder during regenerative braking?
  18. Based on the noise, I believe the damage is much greater than this FAQ seems to imply.
  19. Why was repairing this bearing failure such a big deal initially?
  20. Is this a warranty repair? What about the extended warranty?
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  1. I have started to notice a sound progressively getting louder when I brake and Accelerate but mostly very loud when I am stopping. It sounds like a table saw winding down. This is something that never happened before. What is causing this?
    This sound could indicate a bearing race failure. Symptoms? It sounds terrible – like a saw blade slowing down. A slight ticking sound in reverse, more sound in Drive and even louder in L – the pitch increases with speed, but gets louder at lower speed.

    http://www.youtube.com/watch?v=F2ulyuyBVE8

  2. What kind of damage can I cause by driving the car with this issue?
    If it is a bearing cage failure, it sounds a lot worse than it is. It DOES NOT come into contact with the stator nor does it grind up the core into pieces, nor does it damage the stator. Take it to the dealer. It shouldn't really be a problem driving it another 18 miles (30km) but you can contact OnStar and have it towed to be safe and minimize any collateral contamination (just plastic debris for the most part).
  3. Do I need to have the car towed to the dealer?
    It shouldn't really be a problem driving it another 18 miles (30km) but you can contact OnStar and have it towed to be safe and minimize any collateral contamination (just plastic debris for the most part). There is no serious damage as long as it's dealt with expeditiously. But since the appearance noise is so sudden and obnoxious to your average Volt owner, that really isn’t a problem.
  4. Is there a service bulletin I can refer my Chevy dealer to?
    Yes, have them look up and read the PIP5081H and the replacement procedure in GM's Electronic Service Information system BEFOREHAND. Also make sure they have the proper tools at hand.
  5. What tools are needed by the dealer for the repair?
    These ARE NOT Volt specific tools!
    DT-47865 - Bearing Remover and J-45124 - Removal Bridge
    http://gm-volt.com/forum/attachment.php?attachmentid=40186&d=1385435849
    DT-22928-B Bearing & Seal Installer
    http://gm-volt.com/forum/attachment.php?attachmentid=40178&d=1385435848

  6. How difficult is the bearing repair?
    It's really no different that repairing a conventional automatic transmission (which is FAR more complicated that the internals of the Volt's drive/propulsion unit by the way) in that many can be repaired without completely overhauling the entire unit. This is really no different. BUT it requires the right tools and a trained tech willing and able to follow the published processes for the repair.
  7. Does the repair require removing the transmission?
    The repair is typically done in-car through the LH fender well while the car was up on the lift - all open from underneath (the fender itself isn't removed).
  8. Does the rotor need to be replaced in addition to the bearing cage?
    Rarely. Early on, the rotor was been replaced in a handful of Volts either due to the unavailability of the bearing itself (originally this bearing was not to be a serviceable part i.e. part of the rotor), or unavailability of the special tools needed to properly remove and reinstall it. A bulletin now clearly identifies how to replace the bearing and the correct tools to use. The rotor was also replaced on a couple of cars that had a repeat failure after the bearing alone had been replaced at the dealership.
  9. Does the entire MG-B rotor/stator assembly need replacing?
    Replacing the MG-B rotor/stator assembly really isn’t necessary for the repair to be successful. Instead, it's more an alternative method to obtain a pre-installed bearing in the event ordering the individual part, or the tools necessary to service it cannot be obtained in a timely manner.So the dealer would be well advised to insure they have the tools and parts on-hand BEFORE tearing the drive unit apart. They should look up and read the PIP5081 and the replacement procedure in GM's Electronic Service Information system BEFOREHAND.
  10. Once repaired, can the bearing fail again?
    Possibly, though this is not a chronic issue. Essentially ALL of the repeat failures have been attributed to the repair procedures NOT being followed by the technician. If the Chevy service tech failed to look up or read the PIP5081 and the replacement procedure in GM's Electronic Service Information system BEFOREHAND this could certainly cause a substandard repair and subsequent repeat of the problem. So, there's not much chance of a repeat failure, providing the bearing was properly replaced, as in the technician carefully followed the published process for it's removal and installation. If for whatever reason they do not (e.g. didn’t have the correct tools, or didn’t use them correctly, didn’t follow the detailed instructions for R&R or measuring the bearing race for proper alignment after it's installed, and a couple of additional inspections necessary to insure it's fixed right the first time. etc. etc.) then the repair might NOT be a success, especially if the noise does not alleviate (or returns after a short period of time).
  11. What if the bearing noise problem persists or returns after repair?
    Get your Volt Advisor involved. There's not much chance of a repeat failure, providing the bearing was properly replaced, as in the technician carefully followed the published process for it's removal and installation. If for whatever reason they do not (e.g. didn’t have the correct tools, or didn’t use them correctly, didn’t follow the detailed instructions for R&R or measuring the bearing race for proper alignment after it's installed etc. etc.) then the repair might NOT be a success, especially if the noise does not alleviate (or returns after a short period of time). If the dealer tech had some sort of trouble replacing the bearing they MAY need to replace the complete rotor (comes with the bearing) or even the drive unit assembly in order to remedy the issue.
  12. What causes the bearing to fail?
    Damage to the bearing race during final assembly of the drive unit.
  13. Is failure of the bearing related to driving in Low? Number of miles? The car year?
    No. There is no correlation with driving in Low, or in Drive for that matter. Very few of these have actually occurred and the issue has been identified as potential damage to the bearing race during final assembly of the drive unit.
  14. Is failure of the bearing common?
    No, but it is concerning for those who experience it.
  15. If this bearing failure happens outside the warranty, will it be expensive?
    It's not a difficult or even an expensive repair. The drive unit does not need to be removed. Assuming everything (tools, parts, repair bulletin) is "at hand" it shouldn't take longer than 3-4 hours. Not much more than an old-school tune-up...
  16. How is the whining or table saw noise being created?
    The noise is created by the fact that after the plastic roller cage fails some or all of the bearing rollers are no longer properly/equally spaced around the circumference of the rotor support in the end cover. The rollers are all still there, as they are "captured" within the bearing races but will "gather" together and spin inside the races at what is now an un-natural frequency. This is what creates the “whining” or “table saw” sound. This bearing (as with all ball/roller/needle bearings) is designed for metal to metal contact, within the confines of its races providing there is adequate lubrication (the bearing is pressure fed transmission fluid from an internal passage) so there isn't really any serious metal contamination present OR any damage where on the 2 parts in which the bearing is working in conjunction with- just a noise and a bunch of plastic material scattered through the end cover.
  17. Why is the whining sound louder during regenerative braking?
    The noise is more pronounced during regen because the magnetic fields created between the rotor and stator windings during regen are quite strong which creates certain thrust forces that actually move with the active poles involved, and therefore placing fluctuating loads on the bearing. So technically the noise it ALWAYS there but merely becomes more pronounced under these conditions.
  18. Based on the noise, I believe the damage is much greater than this FAQ seems to imply.
    There's always going to be a few skeptics when someone tells them it sounds worse than it actually is. But there is no serious damage as long as it's dealt with expeditiously.
  19. Why was repairing this bearing failure such a big deal initially?
    There weren't any spare parts or repair procedure. Someone made an educated decision at some point that this particular bearing was not something that would ever require routine replacement (other than when the rotor was replaced). They were obviously wrong in that decision.
  20. Is this a warranty repair? What about the extended warranty?
    The bearing repair is certainly covered under the 3 year/36k bumper to bumper warranty. It seems to me it would also be covered under the 5 year/100k mile power train warranty (the engine, the transmission/transaxle, and the drive train). Any Voltec componenet is covered 8 years/100k miles, but I don't think the bearing would be considered a Voltec component. A GMPP Major Guard warranty extension covers
    "Virtually every mechanical, electrical and electronic component of your vehicle is covered against failure even if it results from wear and tear *. You're covered for parts and labor on:
    Engine
    Transmission / Transaxle
    Front / Rear-wheel-drive components
    Fuel delivery component
    Engine cooling component
    Heating and vehicle manufacturer-installed air conditioning components
    Electrical, computer and audio components
    Braking system components
    Suspension (Front / Rear)
    Steering component
    High-tech components
    Seals and gaskets
    Safety components
Sources:
http://gm-volt.com/forum/showthread.php?66482-Bearing-Failure-vs-Driving-in-L
http://gm-volt.com/forum/showthread.php?89658-Another-Motor-Bearing-Failure
http://gm-volt.com/forum/showthread.php?85658-Stator-Bearing-Failure
http://gm-volt.com/forum/showthread.php?56705-GM-fix-my-Lemon-take-2...
http://gm-volt.com/forum/showthread.php?46489-Fix-my-Volt-Please-Take-1.
 

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Thanks Steverino, puts all those "myths" finally to bed .....

Just wish GM should have put this out at the start, also agree if Tech's don't do it right then it comes back as a boomerang.
(Transmision and bearing replacement work isn't for all techs), seen some locally - cannot even get a race into a wheel hub properly seated - locally like my local Ford dealership!. But there are also some that have a brain - keep things clean and know how to install bearings to seat them evenly unstressed. great info...!

Great info!
 

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Discussion Starter #6
Some,very mild "whine" during regen is normal, right ?
Some mild, almost inaudible whine is normal at low speeds when the car is starting out or slowing. At least, I hear some. Not objectionable or bothersome, though I suppose some with more sensitive hearing may hear more or be bothered. A bearing failure leaves no doubt in the driver's mind that something is very wrong. Dogs start howling and pedestrians will turn to see where the noise is coming from. It's not a subtle thing.
 

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I'm surprised this is still a problem, even if in low numbers. It should be resolved by now!

EDIT: By the way, nicely done on the FAQ though :)
 

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Just making sure...Thanks

Some mild, almost inaudible whine is normal at low speeds when the car is starting out or slowing. At least, I hear some. Not objectionable or bothersome, though I suppose some with more sensitive hearing may hear more or be bothered. A bearing failure leaves no doubt in the driver's mind that something is very wrong. Dogs start howling and pedestrians will turn to see where the noise is coming from. It's not a subtle thing.
 

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Discussion Starter #9
Is it fully covered under the extended GMPP warranty?

Thanks
MrEnergyCzar
The bearing repair is certainly covered under the 3 year/36k bumper to bumper warranty. If it's considered part of the power train—the engine, the transmission/transaxle, and the drive train—(seems like it is part of the power train to me), that warranty is 5 years/100k miles. Any Voltec componenet is covered 8 years/100k miles. I don't think the bearing would be considered a Voltec component. A GMPP Major Guard warranty extension of that would seem to apply as it covers
"Virtually every mechanical, electrical and electronic component of your vehicle is covered against failure even if it results from wear and tear *. You're covered for parts and labor on:
Engine
Transmission / Transaxle
Front / Rear-wheel-drive components
Fuel delivery component
Engine cooling component
Heating and vehicle manufacturer-installed air conditioning components
Electrical, computer and audio components
Braking system components
Suspension (Front / Rear)
Steering component
High-tech components
Seals and gaskets
Safety components
 

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Thank you so much for this post! I just dropped my Volt off at the dealership on Friday because of this whining. I came home and researched it on the internet and thought it was most likely the bearing. The dealership confirmed on Monday. You have answered all my questions except does anyone know what percent of all Volts have had this issue? Is it rising to the level of a recall? (My Volt is a 2012 w/ 38k)
 

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Thank you so much for this post! I just dropped my Volt off at the dealership on Friday because of this whining. I came home and researched it on the internet and thought it was most likely the bearing. The dealership confirmed on Monday. You have answered all my questions except does anyone know what percent of all Volts have had this issue? Is it rising to the level of a recall? (My Volt is a 2012 w/ 38k)
This post may help: http://gm-volt.com/forum/showthread.php?101433-quot-Volt-Issues-Revisited-quot-Im-Back-with-the-Same-Regen-bearing-Noise!!!&p=1375465#post1375465

If anything, I would say the failure frequency now is declining, not rising.
 

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Thank you for your explanation. It was timely because I had just taken my 2012 Volt, 38k, to the dealer for this problem. It was fully covered under warranty and they even paid for a rental car for me as I live 1 hour away from them. They part was ordered on Monday and arrived on Wednesday. The car was fixed on Thursday. They were generous and let me keep the rental until Friday when I could make it back up. Your explanation was greatly appreciated and gave me the info I needed to feel knowledgeable.
 

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Can water enter the bearing area like water used to be able to enter and damage the throwout bearing in older standard shift cars?
 

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Do I need to have the car towed to the dealer?
It shouldn't really be a problem driving it another 18 miles (30km) but you can contact OnStar and have it towed to be safe and minimize any collateral contamination (just plastic debris for the most part). There is no serious damage as long as it's dealt with expeditiously. But since the appearance noise is so sudden and obnoxious to your average Volt owner, that really isn’t a problem.

What if the bearing noise problem persists or returns after repair?
Get your Volt Advisor involved. There's not much chance of a repeat failure, providing the bearing was properly replaced, as in the technician carefully followed the published process for it's removal and installation. If for whatever reason they do not (e.g. didn’t have the correct tools, or didn’t use them correctly, didn’t follow the detailed instructions for R&R or measuring the bearing race for proper alignment after it's installed etc. etc.) then the repair might NOT be a success, especially if the noise does not alleviate (or returns after a short period of time). If the dealer tech had some sort of trouble replacing the bearing they MAY need to replace the complete rotor (comes with the bearing) or even the drive unit assembly in order to remedy the issue.

What causes the bearing to fail?
Damage to the bearing race during final assembly of the drive unit.

Why is the whining sound louder during regenerative braking?
The noise is more pronounced during regen because the magnetic fields created between the rotor and stator windings during regen are quite strong which creates certain thrust forces that actually move with the active poles involved, and therefore placing fluctuating loads on the bearing. So technically the noise it ALWAYS there but merely becomes more pronounced under these conditions.
Are there some things that need updating here?

There seem to be many examples now of second, brass, bearings failing. Consequently, rather than plastic pieces in the box, this will lead to metal fragments. Pretty bad, no? (Are there any photos of the failed brass bearings?)

If the reason for the thing is damage to the race, what damage is done to the brass race, and why/how does it get damaged in the same way? (Metal would bend and dent and doesn't soften, where plastic would crack and chip and soften with temperature.)

On the latter point I requoted, so are we sure that there is always this noise present that propagates via the bearings, or is it meant to be totally silent, as suggested by a few folks?
 

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Most all cases of 2nd failure have been attributed to issues created during the service procedure. Most notably not using the proper tools (or not using them as outlined) or possibly the failure to properly clean debris/contamination created from the initial bearing failure and the recommended use the GM transmission flushing equipment afterwards. In most cases the 2nd failure results in a replacement of either the rotor assembly or the entire drive unit.

WOT
 

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Most all cases of 2nd failure have been attributed to issues created during the service procedure. Most notably not using the proper tools (or not using them as outlined) or possibly the failure to properly clean debris/contamination created from the initial bearing failure and the recommended use the GM transmission flushing equipment afterwards. In most cases the 2nd failure results in a replacement of either the rotor assembly or the entire drive unit.

WOT
Does the cage collapse the same as the plastic cage? I can't really imagine that happening, so I'm trying to picture what is the actual failure, and how is the noise generated?
 

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Thanks for this FAQ, Steverino.

I have kept an ear out for this issue since I bought my 2013. At around 40k miles I started to hear the sound and thanks to the video recordings members have captured I was able to determine my bearing was on its way out.

At 45k, I took it to the dealer, John L. Sullivan, and they took care of it plus the other 3 updates listed for my VIN and it was in the shop for 1.5 days. Not bad considering they had to order the bearing. The turn around period seems much reduced nowadays so if you are experiencing a problem I'd suggest getting it checked out sooner rather than later. I avoided it because I thought my car would be down for weeks.

Thanks again for everyone who has contributed to this Knowledgebase.
 

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how much is it, if the volt is not under warranty?
 

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Discussion Starter #19
how much is it, if the volt is not under warranty?
As far as I know, they have all been repaired under warranty. So, IDK.
 

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I'd still like to know what the cause is.

The race cage failure is a symptom, not the cause. The race cage cannot be the cause of its own failure.
 
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