issue Humming/Whining noise between 40 and 50 MPH?

[warmie@245]

I'm having the same issue with my 2014 Silverado. 5.3 with 3.42 rears. Humming starts at about 45 mph under power and stops when I take foot off of accelerator. Took to dealer today and was advised that 90% of the new trucks do that and there is no fix for it. This is my third Silverado and it s the loudest one I've ever owned. All the reviws on this model talk about how much quieter it is compared to older models. They must not have gone over 45 mph. The dealer told me if it gets worse to let them know and they'd try to find the problem.This is not what I expected from Chevy.I e-mailed GM cust service and am waiting for them to reply.This truck is tw weeks old and has 700 miles on it.

I spoke with a GM cust. serv. rep today and was advised these humming noises aren't normal. She contacted the cust. relations mgr. at the dealer and I have an appointment on 7/15 to meet with the Zone Manager about this issue. I hope it can be resolved. If not this will be the second of my three attempts given to the dealer to rectify the problem. One more and it will fall under the Pa. Lemon Law and i'll be seeing if my new truck has the same Humming sound.

[warmie@245]

 

1. mine is super bad at 55 mph at the shop now . when did they say the shafts will be out to dealers

 

Have you been able to get your problem resolved? My 2014 Silverado has the same problem and the tech. told me he can hear it but "doesn't know where to start" so he left it at that. I didn't. I'm supposed to meet with the zone mgr and dealer cust serv rep in mid july but I can't see any posts where this noise issue has been corrected

[Hansol1977]

Hello this is my first post.

 

I have a 2014 Silverado crew cab 4x4 with 5.3 and 3.42 gears. The truck came from Silao Mexico plant... The truck currently has 7100km and whines from 70-80km an hour, only on deceleration under load and nothing when shifted into neutral. Would this be improper preload? I am curious if certain plants are more prone to whining diff's over others? Also any luck from past posts on what is causing the problem.

 

Thanks in advance

[20Denali22]

My trailblazer hummed and it turned out to be a wheel bearing

[2strokesmoke]

Bad machining, poor quality control this rear end has a few issues like ring and pinion bolt over torqued under torqued, failing bearings, and ring and pinion machining thickness variations, and poorly set gear lash clearances.

 

So yeah, one of these issues you probably have with your rear end.

[14SLTZ71]

I'm having the same issue with my 2014 Silverado. 5.3 with 3.42 rears. Humming starts at about 45 mph under power and stops when I take foot off of accelerator. Took to dealer today and was advised that 90% of the new trucks do that and there is no fix for it. This is my third Silverado and it s the loudest one I've ever owned. All the reviws on this model talk about how much quieter it is compared to older models. They must not have gone over 45 mph. The dealer told me if it gets worse to let them know and they'd try to find the problem.This is not what I expected from Chevy.I e-mailed GM cust service and am waiting for them to reply.This truck is tw weeks old and has 700 miles on it.

I spoke with a GM cust. serv. rep today and was advised these humming noises aren't normal. She contacted the cust. relations mgr. at the dealer and I have an appointment on 7/15 to meet with the Zone Manager about this issue. I hope it can be resolved. If not this will be the second of my three attempts given to the dealer to rectify the problem. One more and it will fall under the Pa. Lemon Law and i'll be seeing if my new truck has the same Humming sound.

Hey Warmie, what was the end result, lemon law or repaired truck?

[14SLTZ71]

Mine does this on deceleration but it's not predictable. I was told that PI # 13430 pinion nut improperly fastened applies to 2014's equipped with 3.73 (GT4) rear axle ratio and locking rear diff (G80).

I was also told that the whinning I am hearing on deceleration is coming from the adaptive valve in the exhaust system.

[2strokesmoke]

I am awaiting a rear end replacement, my rear end has way to much lash and shudders too!

will update everyone shen it is complete.

And yes the recall was for 3.73 gear sets, but the 3.42 is installed on the same line, using same tools....go figure they missed some 3.42 torques also?

[warmie@245]

Just got truck back from dealer. GM sent a factory engineer to oversee the repair. I was told it had something to do with the pinion bearing preload. They had to be retorqued using a special torque wrench. One side was torqued higher then the other.

the dealer rep. said the engineer was writing up something to notify all the dealers of the solution.

Well, the noise is mostly gone,but it still hums between 45-60 when the truck is under load(accelerating) I spoke with the dealer and he is calling the engineer to see what to do next.

Here's the irony. I was given a 2014 Silverado from Enterprise as a loaner. I drove it the same way I always do and not a peep out of it. Same engine 5.3 but I couldn't tell what rear end it had but it had no noise at all.

[14SLTZ71]

Just got truck back from dealer. GM sent a factory engineer to oversee the repair. I was told it had something to do with the pinion bearing preload. They had to be retorqued using a special torque wrench. One side was torqued higher then the other.

the dealer rep. said the engineer was writing up something to notify all the dealers of the solution.

Well, the noise is mostly gone,but it still hums between 45-60 when the truck is under load(accelerating) I spoke with the dealer and he is calling the engineer to see what to do next.

Here's the irony. I was given a 2014 Silverado from Enterprise as a loaner. I drove it the same way I always do and not a peep out of it. Same engine 5.3 but I couldn't tell what rear end it had but it had no noise at all.

Did they replace the bearing or just torque the nut to proper specs?

I am curious how long would it take for the bearings on these trucks to become worn enough to hum after being improperly torqued? If they didn't replace the bearings maybe that is why you still hear some humming.

[warmie@245]

No bearings were replaced. I asked about that and was told everything was checked and mic'd and was o.k. They di replace the Yoke and a universal on their first attempt to repair the noise. The truck only has 3000 miles on it and they said it was fine. I don't think they used the dial torque on the pinion nut itself. They said something about the pre-load had different pounds of torque on the pinion bearing and they adjusted those areas. Hope this helps. I'm not very mechanically astute.

I just hope this can be corrected. all the advertising and reviews about this truck tout how quiet it is. Not so.

[EPIC CAJUN]

Any new news on this? I too have a 14' GMC 5.3 with 3.42 gears and have this humming between 45-50. At 50 its loud enough to hear over the radio at times. Im planning on bringing truck the dealer this week and leaving with them to get it looked at.

[pm26]

Pinion gear shaft has a collapsible spacer and the initial bearing preload must be correct to properly collapse the spacer and preload the bearings. if the pinion shaft nut is too loose, that can cause problems when the pinion gear meshes with the ring gear. In order to have a properly performing rear axle, the following must be met:

 

1. machining quality of gears and the hardness must be sufficient to ensure uniform contact of gear teeth and resistance to wear

 

2. bearings must be of sufficiently high quality to properly resist radial and lateral forces produced by moving parts inside the differential

 

3. Axle housing itself must be properly machined to ensure the parts are in correct orientation to each other.

 

4. parts must be assembled with care, shimmed carefully to obtain correct backlash readings, and correct bearing preloads need to be applied.

 

The last step is crucial because even with the best quality parts, improper assembly will ruin everything. My hunch is that GM is failing in this area.

[calgator73]

Mine does this on deceleration but it's not predictable. I was told that PI # 13430 pinion nut improperly fastened applies to 2014's equipped with 3.73 (GT4) rear axle ratio and locking rear diff (G80).

I was also told that the whinning I am hearing on deceleration is coming from the adaptive valve in the exhaust system.

Copy of the bulletin and symptoms?

[14SLTZ71]

Copy of the bulletin and symptoms?

Here it is.