2015 GMC Denali 6.2/8-speed shifting noise when cold

[f8l vnm]

this is truly sad, sounds like GM just dosent have a clue

[Isriam]

I am having a metal clunking/clapping noise when the truck is stating from a stop when it is cold. Noise only happens if I am starting at a very slow speed in traffic.

If I take off quickly it does not happen. Truck has about 1800 miles on it. It does not happen every time, it stops if I drive it more than 10-15 miles. Won't do it again until it is cold.

I think it's an exhaust or heat shield issue. It's kind of a higher pitch metal slap.

I have not been back to the dealer yet. Anyone else having this issue.

 

this thread is full of a lot of weird information. based on the OP, this happens to everyones truck. roll your windows down and hit the gas and let off a few times. as long as you're under 25 usually you'll hear it. my 2014 has done it since brand new. it sounds like the rear end is about to fall out.

[Ashtonman]

Service Bulletin

 

 

GM Bulletin No.:

Date:

 

 

 

 

14876

December 2014

 

 

 

 

Service Bulletin

 

 

GM Bulletin No.:

Date:

 

 

 

 

14876

December 2014

 

 

 

 

Service Bulletin

 

GM Bulletin No.:

 

Date:

 

14876

 

December 2014

 

SERVICE UPDATE

 

SUBJECT: Service Update for Inventory Vehicles Only

 

8-speed Transmission Harsh Shift

 

Expires December 31, 2015

 

MODELS: 2015 Cadillac Escalade, Escalade ESV

 

2015 Chevrolet Corvette, Silverado Double Cab and Crew Cab

 

2015 GMC Sierra Double Cab and Crew Cab, Yukon, Yukon XL

 

Equipped with 8-speed Automatic Transmission (M5U)

 

This service update involves vehicles in dealer inventory only and will expire December 31,

 

2015.

 

PURPOSE

 

On certain 2015 model year Cadillac Escalade, Cadillac Escalade ESV, Chevrolet Corvette,

 

Chevrolet Silverado Double Cab and Crew Cab, GMC Sierra Double Cab and Crew Cab, GMC

 

Yukon and GMC Yukon XL vehicles equipped with 8-speed automatic transmission (M5U), the

 

customer may complain about harsh shifting. This can occur if the vehicle experienced multiple

 

transmission reprogramming events during manufacturing, causing the calibration to over-adjust

 

the shift parameters. This bulletin provides a service adaptive learn procedure that should be run

 

to reset the calibration to the baseline parameters.

 

This service procedure should be completed on involved vehicles currently in dealership

 

inventory as soon as possible but no later than December 31, 2015, at which time this

 

bulletin will expire.

 

VEHICLES INVOLVED

 

All involved vehicles are identified by VIN in the Global Warranty Management System

 

Investigate Vehicle History Application. Dealership technicians should always check this site to

 

confirm vehicle involvement prior to beginning any required inspections and/or repairs. It is

 

important to routinely use this tool to verify eligibility because not all similar vehicles may be

 

involved regardless of description or option content.

 

Additionally, a list of involved vehicles currently in dealer inventory is available on the Service

 

Update Bulletin Information link under the Service tab in GM GlobalConnect (US) or attached

 

to the GlobalConnect message (Canada) used to release this bulletin. Customer vehicles that

 

return for service, for any reason, and are still covered under the vehicle's base warranty should

 

also be checked for vehicle eligibility.

 

Page 2 December 2014 Bulletin No.: 14876

 

PART INFORMATION

 

No parts are required.

 

SERVICE PROCEDURE

 

Note: Ensure the most recent GDS2 update is installed BEFORE performing the procedure.

 

Note: If the transmission fluid temperature is not between 75°C (167°F) and 85°C (185°F) the scan tool will not allow you to perform the service fast learn procedure.

 

1. Drive vehicle to warm transmission fluid to a temperature range between 75°C (167°F) and 85°C (185°F).

 

2. Connect the MDI to the vehicle.

 

3. Access GDS2 and navigate to the Transmission Adaptive Values Learn screen using the following GDS2 navigation path: Diagnostics>Global Vehicle Selection>Module Diagnostics>Transmission Controls>Configuration/Reset Functions>Transmission Adaptive Values Learn.

 

Note: After the Transmission Adaptive Value Learn procedure is performed, the ignition must be shut off for at least two minutes to ensure the transmission control module shuts down completely before the vehicle is driven. This reboot of the transmission control module is needed before the transmission control module will operate under the new learned values.

 

4. Follow Transmission Adaptive Values Learn on-screen instructions. Refer to Transmission Service Fast Learn Procedure in SI if required.

 

5. Remove MDI from the vehicle.

 

6. Verify transmission shifts into R Reverse and D Drive.

 

WARRANTY TRANSACTION INFORMATION

 

Submit a transaction using the table below. All transactions should be submitted as a ZFAT transaction type, unless noted otherwise.

 

Labor Code

 

Description

 

Labor Time

 

Net Item

 

9101182

 

Perform Transmission Adaptive Values Learn Procedure

 

0.5

 

*

 

* The amount identified in Net Item should represent the actual sum total of the current GMCCA Dealer net price for fuel needed to perform the required repairs, not to exceed $1.50 USD, $2.40 CAD, plus applicable Mark-Up or Landed Cost (for Export).

 

DEALER PROGRAM RESPONSIBILITY

 

Whenever a vehicle subject to this service update enters your vehicle inventory, or is in your facility for service in the future, and the vehicle is still covered under the New Vehicle Limited Warranty, you must take the steps necessary to be sure the service update correction has been made before selling or releasing the vehicle.

I am not sure if my temperature guage for my transmission is working correctly. I have been tracking the temperature after driving more than 10 miles and I can't get it over 150. I was running 40-60 mph. The outside air temperature right now is in the lower 20s. Is this normal for the temperature to run this low after 10 miles? Can anyone else with 8 speed reply with what you are running.

[PMattras]

If you are having this problem I would bring it in and get it on record. Make sure they do any and all updates accordingly and put it on record if there are any further updates you want to be given notice. It sounds like it could be just a software issue which GM is still working on it because it is a new transmission. Maybe this is the reason why GM is slowly introducing this transmission (test market) to avoid too many complaints until they are able to work out all the issues.

[SMiller]

I am not sure if my temperature guage for my transmission is working correctly. I have been tracking the temperature after driving more than 10 miles and I can't get it over 150. I was running 40-60 mph. The outside air temperature right now is in the lower 20s. Is this normal for the temperature to run this low after 10 miles? Can anyone else with 8 speed reply with what you are running.

Completely normal, you will need to block the cooling system (grill) to bring the temps up.

[BluByU14]

Just picked up my truck from the dealer. They performed the service bulletin listed above and the transmission so far seems to shift much better. There is still a fairly pronounced "clunk" once you begin from a stop and even when you put it in reverse and lightly touch the accelerator. Service dept said they couldnt hear it. It usually gets worse as the vehicle gets warmed up...... it doesnt seem to affect the performance of the truck, just annoying and semi concerning.

[GMCustomerService]

Just picked up my truck from the dealer. They performed the service bulletin listed above and the transmission so far seems to shift much better. There is still a fairly pronounced "clunk" once you begin from a stop and even when you put it in reverse and lightly touch the accelerator. Service dept said they couldnt hear it. It usually gets worse as the vehicle gets warmed up...... it doesnt seem to affect the performance of the truck, just annoying and semi concerning.

 

Hey BluByU,

 

I'm sorry to hear about this concern with your truck and I understand how this would be something you would like to get an answer to. I would like to look into this further, to try and get more information for you about this 'clunking'. You are more than welcome to send me a private message with your VIN, contact information, preferred dealership and current mileage. I look forward to hearing from you soon and seeing how I can assist.

 

Anisha T.

GM Customer Care

[Ashtonman]

I finally had a chance to return to my GMC dealer today. They updated my transmission software again. They found PI1338 relating to shifting that was released on the 17th. It actually seems to improve the shifting. I have 3100 miles and it was getting bad. I will know if it really changed anything tomorrow morning because it always shifts bad when it is cold.

[TX14Z71]

I finally had a chance to return to my GMC dealer today. They updated my transmission software again. They found PI1338 relating to shifting that was released on the 17th. It actually seems to improve the shifting. I have 3100 miles and it was getting bad. I will know if it really changed anything tomorrow morning because it always shifts bad when it is cold.

Please let us know.

[Ashtonman]

Update, the shifting has improved dramatically. I would recommend anybody with an eight speed to get to the dealer for the new update. I still have the metal on metal slapping sound (clunk) when I take off from start when it's cold. I guess the truck needs to spend the night at the dealership out in the cold and then theyneed to drive it first thing in the morning to hear the metal clunk.

[BluByU14]

Update, the shifting has improved dramatically. I would recommend anybody with an eight speed to get to the dealer for the new update. I still have the metal on metal slapping sound (clunk) when I take off from start when it's cold. I guess the truck needs to spend the night at the dealership out in the cold and then theyneed to drive it first thing in the morning to hear the metal clunk.

That sounds exactly like my truck......the update made a world of difference to mine, but still have the dealer figuring out the metal clunk. Mine is actually worse when it gets warmed up.

[BluByU14]

Just received a call back from my dealer. They said that there were able to duplicate the clunk I was describing. The got underneath of it determine it was one of the rear springs making the "learch" upon take off or even in reverse. The called GM to go through this with them and said it was "normal".

 

Transmission is running great after that last service update!

[BluByU14]

 

 

Just received a call back from my dealer. They said that there were able to duplicate the clunk I was describing. The got underneath of it determine it was one of the rear springs making the "learch" upon take off or even in reverse. The called GM to go through this with them and said it was "normal".

 

Transmission is running great after that last service update!

 

 

As reported previously, the dealer has successfully updated my transmission to shift much better then when I took delivery of it back in December. I still had a "clunk" every once in a while from a take off or when putting the transmission into Reserve. The clunk was not loud, nor did i shake the vehicle or cause any sort of performance issues with the rig (just annoying). Dealer said that it is completely normal......I guess at this point, I will keep runn'er and if it gets worse, just take it back in. Below is the service bulletin the dealer gave me:

 

[lba0213]

Thanks for the update. To me it sounds like GM is trying to justify this clunking noise and making sure their dealers are on board. Pathetic.

 

On another note. You mentioned a tranny update released on the 17th, did that refer to the 17th of january 2015? You dont have the actual bulletin to post on here do you? Id love to show this to my dealer.

 

Thanks

[BluByU14]

Thanks for the update. To me it sounds like GM is trying to justify this clunking noise and making sure their dealers are on board. Pathetic.

 

On another note. You mentioned a tranny update released on the 17th, did that refer to the 17th of january 2015? You dont have the actual bulletin to post on here do you? Id love to show this to my dealer.

 

Thanks

 

 

Sorry about that.....it was service #: 14876. The details of the service bulletin are listed on page one of this post. I think it was released sometime in last December 2014.

 

Hope that helps!