Denali Drivetrain noise when in AUTO

[mongoose71]

I have about 73K miles on my Sierra Denali and have recently developed a whining noise when I have the transfer case selected to AUTO.  Has anyone else experienced this issue, and determined what the cause is?

[truckguy82]

1 hour ago, mongoose71 said:

I have about 73K miles on my Sierra Denali and have recently developed a whining noise when I have the transfer case selected to AUTO.  Has anyone else experienced this issue, and determined what the cause is?

Mine has been like that since new. As far as I know every 4auto truck makes the noise.

[newdude]

Is it an electrical high pitch whine?

[mjm1957]

Run it on a lift in four high and check the front diff. We just did two more last week. Pretty common on the 1500's. If you hear the noise from the diff drain the oil and check for metal.Hope you have extended warranty.

[mongoose71]

Mine hasn’t always made this noise, it just started. I’m going keep it in 2 high until I have time to get it checked out.


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[btj_z71]

Check the fluids in the front diff and transfer case.

[300 Blackout]

Mine hasn’t always made this noise, it just started. I’m going keep it in 2 high until I have time to get it checked out.

About how many miles are on the truck in AUTO? While auto can be used in all driving conditions without causing major damage to the vehicle, it does wear out parts, fluid, etc... in the front diff much quicker and will require more frequent service. If there are a lot of miles in AUTO, then a good place to start would be the front differential fluid as others have mentioned. The fluid is most likely oxidized/worn out and providing limited if any lubrication and the noise you hear is your gears or bearings wearing. If it doesn’t go away after a fluid change, then a trip to the differential shop or dealer is in order.

[20165.3Eco]

Mine has made a slight growling noise under accelerating since I purchased it with 20,000 miles. I drove it about 200 miles once towing in Auto on accident and with the AC on I didn't notice the noise on that trip. 

 

My buddy bought a new 2016 new off the lot and his has the same noise since new. 

[2017Darkness]

Why o why are you driving around in AUTO all the time??? YUUUGE NO NO

[mongoose71]

I swap it to Auto during rainy weather and sometimes forget to swap it back.

[20165.3Eco]

Auto won't hurt anything, it serves a similar function as a full time AWD vehicle.

 

I really only use mine to get into fast moving traffic in the rain and for normal snowy driving. Also helpful on boat ramps because it doesn't hop around and bind up when you turn. 

 

I was always a man truck kind of guy 4x4 lock or nothing but owning this I have found auto very helpful. 

[mongoose71]

I'm planning on swapping both diff. fluids as well as the transfer case soon to see if this will help.  Any advice on what brands or weights that I should go with would be appreciated. 

[2017Darkness]

 

 

Condition/Concern

Some customers may comment on a high pitched whine noise from the vehicle noticed when driving in auto 4wd.

The customer may comment that it is an intermittent noise and no noticeable pattern to when it can be heard.

Recommendation/Instructions

The transfer case control module on these vehicles is located next to the accelerator pedal and is not covered by any close out or hush panels.

When the transfer case control module has to move the transfer case actuator motor the higher current passing through the module causes an "electronic buzz or whine" within some of the capacitors in the module that can be heard by some of our customers.

The latest transfer case control module in service parts has provisions to eliminate this noise. Replace transfer case control module with current part number in the catalog. When programming the module ensure that the description for the calibration installed states the following "New software (Version 9.2) to address field issue of setting DTC C0398 while being driven in AUTO mode for 1 hour due to the IPS sensor drifting."

 

Might have something to do with your issue, but you're still gonna want to service that front diff. It is not designed to be driven in Auto for long periods of time on dry pavement.

[mongoose71]

38 minutes ago, 2017Darkness said:

 

 

Condition/Concern

Some customers may comment on a high pitched whine noise from the vehicle noticed when driving in auto 4wd.

The customer may comment that it is an intermittent noise and no noticeable pattern to when it can be heard.

Recommendation/Instructions

The transfer case control module on these vehicles is located next to the accelerator pedal and is not covered by any close out or hush panels.

When the transfer case control module has to move the transfer case actuator motor the higher current passing through the module causes an "electronic buzz or whine" within some of the capacitors in the module that can be heard by some of our customers.

The latest transfer case control module in service parts has provisions to eliminate this noise. Replace transfer case control module with current part number in the catalog. When programming the module ensure that the description for the calibration installed states the following "New software (Version 9.2) to address field issue of setting DTC C0398 while being driven in AUTO mode for 1 hour due to the IPS sensor drifting."

 

Might have something to do with your issue, but you're still gonna want to service that front diff. It is not designed to be driven in Auto for long periods of time on dry pavement.

Thanks, that could be what I was hearing. The pitch of the sound would increase as I press the accelerator pedal and would quieten as i coast.

[20165.3Eco]

Yes it is, you will prematurely wear items out (Dif and T case maybe) but be design it wouldn't hurt a thing to drive around in 4 Auto on dry pavement. 

 

My truck had the T case control module replaced because of the high pitched screeching noise. This noise only happened when it was directing power to the front wheels or shifting in and out of any drive mode. If you still have noise under deceleration this is probably not the issue. 

 

 (From GMCs Website)

AUTOMATIC 4 HI
If road conditions frequently alternate between high- and low-traction areas, consider using the “AUTO” setting found on select GMC electronic transfer cases. This setting allows your GMC to automatically distribute torque to the front axle by anticipating the need for additional traction.  Shifting into “auto” engages the front axle, but the transfer case sends power primarily to the rear wheels in normal conditions and the clutches modulate torque forward to provide stability and enhance traction to the vehicle.  Although not always optimal for efficiency and wear of your vehicle 4wd driveline, AUTOMATIC 4 HI can be used on any road condition without risk of damaging your vehicle.