2014 Sierra humming noise

[jcchevy]

Any new light to shed on this issue? I just bought a 2014 1500 crew cab, 5.3, 4X4, LTZ, 3.42 gears. Very noticeable on and off humming/frequency noise (and I think I also feel it on te floor boards) that is especially noticeable from 60-70mph. It is not engine rpm based, nor is it V4 or V8 based. It seems to be noticeable once the truck has been driven and all the fluids are warmed up a bit. It does go away when in "auto 4 wheel drive" and then slowly comes back when switched back into 2WD. Please help me point to a technical service bulletin or a fix of some sort!

(EDIT: Updated Correct Differential Part Number)

Thanks for the detailed description majicgoats, Thats important on these forums. If you bought used, the previous owner probably was sick of that issue as well and traded it in.

Based on your descriptive issue, you have a defective front axle. You can read my previous posts on this topic. My first one became defective around the 4K mile mark, a year later I was able to twist (hard) the arm of the Service Dept , got them to replace it finally (they are a good service dealer, but per GM they don't suppose to replace front differential if its still functional, which technically in GM's terms it was) and the issue was resolved and no more noise. Was smooth as glass.

 

That excitement was unfortunately short lived, about 1K miles later the new diff (same part number as previous as i took pics before after, only SN changed) started the same thing, only good thing is its not as bad as the first (yet).

Below are some info in regards to what (IMO) is the root cause which would be a defective carrier bearing going bad/bad defective part in the assembly line and would cause this rumble strip vibration humming noise.

There is currently NO service bulletin, There is currently NO resolution from GM.

Front Axle (entire axle) part#:GM Part No. 23186399 ($1000-1500) part.

Description of issue and fix=what GM should do

Belly Growl

Problem: Low-pitched growl emitting from the axle at speed. It can sound like tire drone, and you may not notice it at low speeds. Sometimes accompanied by vibration.

Fix: If it’s a carrier bearing it typically requires a total axle rebuild because metal shavings have probably damaged other components in the differential. However, in rare cases if it’s caught early you may get by with just replacing the carrier bearings. Rule of thumb: If the carrier is loose, the axle will probably need to be rebuilt.

 

Resource from: http://www.fourwheeler.com/how-to/transmission-drivetrain/129-1207-identifying-bad-axle-noises/#ixzz3RLoOOryZ

 

Edited February 11, 2015 by GM-GUY

[majicgoats]

Thanks for the response GM-GUY. I have a scheduled appointment for this Thursday (02/12/2015) to hopefully address this issue and a couple others. I will keep everyone posted as to this process. I bought my truck with 250 or so miles on it about 2 weeks ago and noticed the issue on my way home from the dealer...which was a 220 mile drive. My truck now has 1,100 miles on it. I have already called GM directly to complain about the issue and was given an "open case number" and was told to let them know if the dealer can't resolve the problem. I am curious as to whether the part number GM-GUY gave for the new entire front axle is the original part number or one that has been "updated/fixed" that supersedes the original.

Edited February 12, 2015 by majicgoats

[jcchevy]

...I am curious as to whether the part number GM-GUY gave for the new entire front axle (89021671) is the original part number or one that has been "updated/fixed" that supersedes the original.

 

(EDIT, I originally jotted down incorrect part number, that was actuallty for the GM diff lube) this post is now updated with the correct part #)

I custom built to ordered my 2014 denali, picked up from dealer Nov 2013. Front Axle Part number was (23186399). My brand new replacement front axle part number was the same. ( which was installed Nov 2014). You can check on the sticker on outside of your own diff to check part number. And from my research its the same front axle (and part number) that was in the previous 1500 series generations. Just think they (drive line assembly manufacture line) quality really went down hill or even more specifically a huge batch of bad carrier bearings. Because how coincidence to have two axles (1 yr a part, not to say it wasn't from 2013 and just sat on a shelf at GM for a year) both bad, one little better then other, but still both same issue.

Edited February 11, 2015 by GM-GUY

[tbarn]

I can see why you had to strong arm the dealer to get an entire axle assembly. We almost never replace assemblies.

[jcchevy]

I can see why you had to strong arm the dealer to get an entire axle assembly. We almost never replace assemblies.

Correct. Its a difficult situation GM puts dealers and customers in. As long as the wheels go round and round, the diff "isn't defective" Thats why all the guys with the particular symptoms/ issue are out of luck for a resolution to their issue unless they truly break their front axle.

[DRS 95 Silverado]

 

Thanks for the detailed description majicgoats, Thats important on these forums. If you bought used, the previous owner probably was sick of that issue as well and traded it in.

Based on your descriptive issue, you have a defective front axle. You can read my previous posts on this topic. My first one became defective around the 4K mile mark, a year later I was able to twist (hard) the arm of the Service Dept , got them to replace it finally (they are a good service dealer, but per GM they don't suppose to replace front differential if its still functional, which technically in GM's terms it was) and the issue was resolved and no more noise. Was smooth as glass.

 

That excitement was unfortunately short lived, about 1K miles later the new diff (same part number as previous as i took pics before after, only SN changed) started the same thing, only good thing is its not as bad as the first (yet).

Below are some info in regards to what (IMO) is the root cause which would be a defective carrier bearing going bad/bad defective part in the assembly line and would cause this rumble strip vibration humming noise.

There is currently NO service bulletin, There is currently NO resolution from GM.

Front Axle (entire axle) part#:GM Part No. 89021671 ($1000-1500) part.

Description of issue and fix=what GM should do

Belly Growl

Problem: Low-pitched growl emitting from the axle at speed. It can sound like tire drone, and you may not notice it at low speeds. Sometimes accompanied by vibration.

Fix: If it’s a carrier bearing it typically requires a total axle rebuild because metal shavings have probably damaged other components in the differential. However, in rare cases if it’s caught early you may get by with just replacing the carrier bearings. Rule of thumb: If the carrier is loose, the axle will probably need to be rebuilt.

 

Resource from: http://www.fourwheeler.com/how-to/transmission-drivetrain/129-1207-identifying-bad-axle-noises/#ixzz3RLoOOryZ

 

 

I know that guy that helped with the article. Lives just a few miles from me. Be interesting to take him for a ride in mine and get his opinion. Mine doesn't do it too bad but it's like magicgoats, kinda comes and goes. Has to have just the right load on it. I thought maybe it was the exhaust system at first. Just never sounded like a differential problem to me.

[kgweststar]

New differential got rid of my noise. Hoping the relief lasts. They mentioned the bearing rubbing on the housing. More oval than round. this fix will keep me sane for now.

[jcchevy]

New differential got rid of my noise. Hoping the relief lasts. They mentioned the bearing rubbing on the housing. More oval than round. this fix will keep me sane for now.

 

Glad to hear. Good feeling isn't it? the return of sanity Just wanted to make a note, I have updated my Differential part numbers I previously posted, both original and 1yr later replacement were both Part# 23186399.

 

When you get a chance check the sticker on the outside of your front diff and see if the part number is the same. If it is, you have a 50/50 chance (like i did) of it being defective. My new one is defective, but its not as bad as my last one (yet).

 

I am actually looking for an upgraded /aftermarket front differential. I have the bigger rear differential due to the 6.2L engine, but they didn't touch the front diff.

if anybody knows of an aftermarket (purchase entire front diff, install myself) type of company, let me know.

Edited February 11, 2015 by GM-GUY

[majicgoats]

New differential got rid of my noise. Hoping the relief lasts. They mentioned the bearing rubbing on the housing. More oval than round. this fix will keep me sane for now.

[majicgoats]

Just wondering (for those that have had luck getting the "appropriate fix" of replacing the front differential) if you have any pointers on what conversations were had to help convince the dealer to make the repair.

[kgweststar]

@majicgoats...I contacted the GM executive office will a confident confirmed noise that dealers are not cooperating with me on fixing. Stressed the disappointment of money spent and malfunction I was experiencing. They had a factory rep come to dealer and drive my truck. Noise confirmed, a little slap to the dealer, and presto! Fixed. ?. Ask for Mary Bara 1-313-556-5000.

*with

[kgweststar]

I think it's extension 21752

[majicgoats]

Update: Just got back from the dealer. Service tech verified the noise and agreed there was an issue at hand. (I was also there to get my starter replaced) the service manager told me that he would "do some looking into the issue" and "make some phone calls" and get back to me at a later time. I told the service manager that my research has not surfaced a TSB and that if they are also unable to find a TSB that I still wanted the issue resolved/fixed. The service manager at that time was not planning on even recording in their system that I was there addressing the issue and wasn't planning on providing any documentation showing that they were able to confirm the noise. I then insisted that I be provided some documentation for the visit. The service manager eventually agreed to "log it" into their system regarding my complaint and visit and the fact that they were able to duplicate it. after being provided with a copy of the "documentation" I was told to give them a call after about a week so I can then inquire as to "what they find out" and to discuss further resolution. I will be sure to call them back one week from today. (FYI GM-GUY, I did buy my truck new...not used. I saw that you were questioning that in a previous post... Currently my truck has 1,100 miles on it.)

Edited February 12, 2015 by majicgoats

[saltybrad]

I bought a '15 GMC 2500 Denali and have been very disappointed to have the same maddening "hum" It was really accentuated after I put on a leveling kit. Knowing it is a drive shaft/diff issue is a huge help. Keep the info coming and I will do the same. Thank you

[majicgoats]

For those that have been following my issue/experience: I was told at my service appointment which was one week ago today to contact them back in one week to see if they have figured out what they will be doing to repair my truck. I contacted the dealer today. I was informed that the dealer service rep. was up a day or two ago and they discussed my trucks issue. Dealer informed that the service rep. is going to do some "looking into it" and will be getting back to the dealer in a couple days for a suggested next step. So far I feel like the dealer is dotting their "I's" and crossing their "T's" before coming informing me of the plan for repair. I will attempt to be as patient as I can why the dealer comes up with the correct "plan of action".