2014 Sierra humming noise

pm26 · March 22, 2015

I wonder when GM is actually going to acknowledge that this IS an issue...

They already have. The "issue" is a "NORMAL OPERATING CHARACTERISTIC" AND "NO REPAIRS SHOULD BE ATTEMPTED."

Oli4 · March 23, 2015

They already have. The "issue" is a "NORMAL OPERATING CHARACTERISTIC" AND "NO REPAIRS SHOULD BE ATTEMPTED."

There is no logic in that. I'll tell you why.

Why is GM building the 'quietist cab ever' then?

To fill it up with 'normal operating noises'?!

http://www.ispot.tv/ad/72aZ/2014-chevrolet-silverado-quiet-cab

Oli4 · March 24, 2015

GUYS! MY TRUCK IS FIXED!

Dealership replaced:
1 Pinion Bearing #15286375
1 Bearing #9413427
2 Differential Side Gear Bearings #20997053
1 Seal (frt diff drv p/gr) #12471590
1 Spacer #12479162
2 Gaskets #15270969 and #15270970
1 Adjuster #15876533
1 Seal #22761722
And of course filled it back up with synthetic gear lube.

The tech's comment was: removed the front diff and inspected it. Upon inspection, discovered scored bearings on the carrier side of the diff. Overhauled and replaced front diff bearings. Test drive ok.

Truck is quiet! FINALLY!!! I had forgotten how that felt.

Funny how a bearing can completely ruin the experience you have with a vehicle. This is now a new truck and I am falling in love all over.

Fingers crossed the scored bearing wasn't a result of something else...

jcchevy · March 24, 2015

@Oli4, congrats on being persistent and basically getting a new front diff in order to resolve it. Welcome to the new front differential club. We all must have got a bunch of Friday made differentials. But your are right, did something externally cause this, or did the manufacturer of the diffs gearing really sucked it up lately (AAM i believe). Since these are the same front generic 1500 series GM truck front diffs/ part numbers going back in previous models.

majicgoats · March 26, 2015

Another update: I phoned my dealer again today requesting what the game plan is to fix my variable humming issue that I have been posting about. Dealer said that he just got back from a service conference and talked to engineers regarding the issue and they have informed him that my issue is due to "improperly cut rear differential gear teeth". I set up another appointment for April 6th to have it looked at. Based on my extensive research and after reviewing other same issues and fixes I am not confident that this problem is a rear differential issue. I am confident the issue is coming from the front differential but if the dealer wants to start at the back end and work their way forward then so-be-it. :/

GMCustomerService · March 28, 2015

Another update: I phoned my dealer again today requesting what the game plan is to fix my variable humming issue that I have been posting about. Dealer said that he just got back from a service conference and talked to engineers regarding the issue and they have informed him that my issue is due to "improperly cut rear differential gear teeth". I set up another appointment for April 6th to have it looked at. Based on my extensive research and after reviewing other same issues and fixes I am not confident that this problem is a rear differential issue. I am confident the issue is coming from the front differential but if the dealer wants to start at the back end and work their way forward then so-be-it. :/

Hi Majicgoats,

We do look forward to all of your updates, and know that we are here to possibly look into this further for you. This is definitely a frustrating experience that would never want you as our customer to experience. Feel free to send us a private message if additional assistance is necessary.

Patsy G

GM Customer Care

warmie@245 · March 30, 2015

I hope you guys all have better luck then me on this "humming above 45mph" issue. I've been told my Silverado humming noise is normal operating noise by 3 GM Engineers. I've also been told after the diagnosis by the engineers that the noise was tiore noise. This from a GM technician at another dealer.That's after a zone mgr and another GM engineer told me it was "harmionic Distortion" before they changed the yoke to no avail. This is all experienced on the "QUIETEST SILVERAD EVER PRODUCED" by GM.

All I can say is Forget It when it comes to getting your noise issue corrected. I've seen but one post where it was corrected by a Technician whoi took the tinme and effort to fix it. When I sent that pst to GM they agreed to let me go to another dealer for a diagnoseis. I gave that dealer the post and was amazed to have the Tech tell me all the previous engineers and managers were incorrect and it was road noise that just happened to start about 50 mph and amazingly go away at about 65mph.

rudie20 · April 1, 2015

I had the same problem but the noise ended up blowing a hole in the front diff case! I put a link to my post below. In summary, mine was grinding/humming then blew apart. Now it is dealer rebuilt (because GM doesn't offer full front diff assemblies) and hums under load. I work in the axle industry and the noise sounds like the hypoid gear adjustment is out of spec and it has improper tooth contact that is only heard under load. If this is the case, the bearings will fail prematurely. Anyway it is now back at the dealer and they don't know what to do. Frustrating.

http://www.gm-trucks.com/forums/topic/171347-2014-sierra-front-diff-issues/

pm26 · April 3, 2015

I hope you guys all have better luck then me on this "humming above 45mph" issue. I've been told my Silverado humming noise is normal operating noise by 3 GM Engineers. I've also been told after the diagnosis by the engineers that the noise was tiore noise. This from a GM technician at another dealer.That's after a zone mgr and another GM engineer told me it was "harmionic Distortion" before they changed the yoke to no avail. This is all experienced on the "QUIETEST SILVERADO EVER PRODUCED" by GM.

All I can say is Forget It when it comes to getting your noise issue corrected. I've seen but one post where it was corrected by a Technician whoi took the tinme and effort to fix it. When I sent that pst to GM they agreed to let me go to another dealer for a diagnoseis. I gave that dealer the post and was amazed to have the Tech tell me all the previous engineers and managers were incorrect and it was road noise that just happened to start about 50 mph and amazingly go away at about 65mph.

Perhaps they should call it "THE HUMMIEST SILVERADO EVER PRODUCED BY GM".

jcchevy · April 3, 2015

... Now it is dealer rebuilt (because GM doesn't offer full front diff assemblies) and hums under load. ...

http://www.gm-trucks.com/forums/topic/171347-2014-sierra-front-diff-issues/

Hi @rudie20, if you read in previous posts, you will see I received a complete new front axle assembly (although 6 months ago) and so did another. Maybe they are going through the complete front diff assemblies too fast to keep up?? Only takes 1/2 hour to replace a full front diff assembly vs many hours to repair one, set gear alignment and the like.

For those having the issue and want a resolution, you can buy your own entire front differential assembly (applies to both 2014/2015 1500 series trucks) for around $1K , its simply a bolt on installation for the most part.

http://www.gmpartscenter.net/oe-gm/23186399

Of course, since its the same OEM GM product (same manufacturer making these), its probably going to have a 50/50 chance being built with same issues/problems giving you a humming machine, or blown hole through your diff as @rudie20 achieved.

I would love to find a aftermarket beefed up one to replace it entirely. There are not many (ok, none) qualified axle shops around my area I would have undertake that, otherwise I would do that route.

majicgoats · April 3, 2015

Hi Majicgoats,

We do look forward to all of your updates, and know that we are here to possibly look into this further for you. This is definitely a frustrating experience that would never want you as our customer to experience. Feel free to send us a private message if additional assistance is necessary.

Patsy G

GM Customer Care

kylek · April 4, 2015

Thanks to kgwestar, I went to my dealer a few weeks ago (in Vegas) and shared his information, telling them I have the same issue. They had trouble isolating it (not sure why), but they acknowledged it and replaced the front differential. All is well now.

majicgoats · April 4, 2015

Kylek, glad to hear you got yours fixed! I am still looking forward to my next dealer appointment on April 6th, 2015 in hopes for them to make the repair. I'd like to say I have high hopes but they most recently told me the issue is coming from the rear end so that is where "they want to take a look". Would you (or any others) that have had a successful fix mind private messaging me with information as to any "case numbers" with gm or your dealer information? I am looking for anything that I may help my dealer get this fixed sooner than later.

majicgoats · April 7, 2015

Hi @rudie20, if you read in previous posts, you will see I received a complete new front axle assembly (although 6 months ago) and so did another. Maybe they are going through the complete front diff assemblies too fast to keep up?? Only takes 1/2 hour to replace a full front diff assembly vs many hours to repair one, set gear alignment and the like.

For those having the issue and want a resolution, you can buy your own entire front differential assembly (applies to both 2014/2015 1500 series trucks) for around $1K , its simply a bolt on installation for the most part.

http://www.gmpartscenter.net/oe-gm/23186399

Of course, since its the same OEM GM product (same manufacturer making these), its probably going to have a 50/50 chance being built with same issues/problems giving you a humming machine, or blown hole through your diff as @rudie20 achieved.

I would love to find a aftermarket beefed up one to replace it entirely. There are not many (ok, none) qualified axle shops around my area I would have undertake that, otherwise I would do that route.

GM-GUY,

The front differential assembly doesn't appear to be complete with gears. (http://www.gmpartscenter.net/oe-gm/23186399) When you received your new axle assembly replacement, did it come with all the internal components preshimmed and ready to go?

majicgoats · April 7, 2015

UPDATE: I dropped my truck off at the dealer yesterday (04/06/2015) for further investigation and repair. The service manager wanted to go for another test drive and again he confirmed the complaint. I just got a call from the service manager today informing that they ordered a new front differential assembly for my truck! I am looking forward to getting the truck back and no longer having to listen to that coming-and-going humming noise. Once I get the truck back I will let you know the results. (P.S. - My dealer was nice enough to provide me a comparable truck while mine is getting fixed...I am thankful of that and it goes a long way with showing customer appreciation and understanding to the frustrations of this issue. )