10 speed Transmission issues banging.

coleyrd1 · December 10, 2020

I have a 2019 GMC Sierra 6.2L Denali, 10 speed transmission, with 36K miles on the truck. I have recently noticed when the truck decelerates more than 20 mph, and then if I accelerate, I hear a single bang sound coming from the transmission as soon as I start to accelerate. It is like the transmission is not prepared to go into the lower gear and jams itself into gear to accelerate. There is no delay in the acceleration that I can tell, but it is a noticeable bank or thud sound of metal on metal. Once it is in gear, it accelerates as normal, and there are no other sounds. This will only happen after the truck has warmed up 10+ min and does not happen if I decelerate less than 18-20 mph. It does not happen as often if I use the brakes to slow down. Also if I come to a complete stop it does not happen and will only happen if the truck is already in motion above 10mph or so.

I took it to the local GM dealer yesterday, and they said they were not familiar with the problem, but it is definitely not right. The dealer talked with GM tech support, and GM said they have heard of the problem but did not have a solution. GM said to take out the transmission and inspect for any visual issues. If no visual issues could be found, then they would replace the transmission. Has anyone else experienced this problem? Any advice moving forward?

Side note- This truck was one of the first sold in our area of the 2019 body styles. I got it in august of 2018. It had the leaking back window issue, and they replaced the window after a 2-3 month delay getting the part in and trying to fix it with sealant.

Thank you in advance for your help.

Edited December 10, 2020 by coleyrd1

redwngr · December 11, 2020

I don't recall anyone posting in the about that one.

How many miles on it when the issue first appeared?

coleyrd1 · December 11, 2020

11 hours ago, redwngr said:

I don't recall anyone posting in the about that one.

How many miles on it when the issue first appeared?

Its hard for me to say honestly. Probably early on but it was not very noticeable. It has recently gotten much worse over the last 5K miles or so. Dealership said yesterday they ordered a new transmission and should have it put in by middle to end of next week. It seems to be working out well so far.

coleyrd1 · December 18, 2020

Just got the truck back with the new transmission and it is still making the noise. Guess I will bring it back to them. It almost sounds like the sound a driveshaft makes when it is first engaged. Not sure if that makes any sense or not. I will try to get a video of it.

BIGDOGx · December 18, 2020

1 hour ago, coleyrd1 said:

Just got the truck back with the new transmission and it is still making the noise. Guess I will bring it back to them. It almost sounds like the sound a driveshaft makes when it is first engaged. Not sure if that makes any sense or not. I will try to get a video of it.

Sounds more like a potential axle wrap problem the k series trucks had or the famous old slip yoke clunk. When GM states that loud bangs are normal from their drivetrains, sadly they are telling the truth.

My 95 s10 zr2 had driveline clunk noises, my 05 silverado had driveline clunk noises and you guessed it my 2014 is also no different. It will clunk on deceleration like you said and it will clunk when going off and back onto the gas. Was hoping the 10 speed might of solved their constant driveline slop issues, but looks like it is jut a characteristic of gm vehicles today, or at least their truck and large suv line as it has been prevlient for decades now with their product imo.

Edited December 18, 2020 by BIGDOGx

bjr2020 6.2 · December 20, 2020

My truck seems good. No clunk on decel my 2015 6.2 had it only way I could get rid of it was to hp tune the truck which I understand isn’t a option for you probably with warranty but my 2020 6.2 seems way better then my 2015.

flyingfool · December 21, 2020

see if they can to the "fast learn procedure" on the 10 speed.. i did this on my 6 speed and it cleaned up the shifts. you need HPtuners or GMs computer interface tool

Edited December 21, 2020 by flyingfool

19 Denali ultimate · December 22, 2020

To me it sounds more like a little excess play in the rear diff gears.

Sebas1999 · December 8, 2021

@coleyrd1 did you ever fix the banging on your truck im having the same problem i have a 2019 denali 10 speed and i noticed it does it when you drop gears and you drop to 2 it bangs

DAVE WHEELER · December 31, 2021

My trans. is much worse than the complaints I have to date. False neutrals under hard acceleration and a bang that should have blown it to pieces by now. Slow to engage drive and reverse when cold. Problem began while towing a 15k lb 5th wheel in tow mode punching it up an onramp. It's at a dealer now and got some TSB update. They said is was done but the lot man parking it reported to the service writer "something is wrong with the trans." sooo standing by for answers.

redwngr · January 2, 2022

On 12/31/2021 at 10:14 AM, DAVE WHEELER said:

My trans. is much worse than the complaints I have to date. False neutrals under hard acceleration and a bang that should have blown it to pieces by now. Slow to engage drive and reverse when cold. Problem began while towing a 15k lb 5th wheel in tow mode punching it up an onramp. It's at a dealer now and got some TSB update. They said is was done but the lot man parking it reported to the service writer "something is wrong with the trans." sooo standing by for answers.

your 3500 has a different 10 speed in the 1500's

Kilgore Trout · January 3, 2022

On 12/18/2020 at 9:26 AM, coleyrd1 said:

Just got the truck back with the new transmission and it is still making the noise. Guess I will bring it back to them. It almost sounds like the sound a driveshaft makes when it is first engaged. Not sure if that makes any sense or not. I will try to get a video of it.

Sounds like they eliminated the transmission as a possible source of the noise. If you have another dealership within reasonable driving distance (could be a Chevy dealer just as well), maybe take it to them and tell them what has been done so far, maybe they have someone on staff that has seen a similar problem before. If they get it right away, maybe consider switching dealers for work going forward.

John Lock · January 6, 2022

On 12/10/2020 at 7:45 AM, coleyrd1 said:

I have a 2019 GMC Sierra 6.2L Denali, 10 speed transmission, with 36K miles on the truck.  I have recently noticed when the truck decelerates more than 20 mph, and then if I accelerate, I hear a single bang sound coming from the transmission as soon as I start to accelerate.  It is like the transmission is not prepared to go into the lower gear and jams itself into gear to accelerate.  There is no delay in the acceleration that I can tell, but it is a noticeable bank or thud sound of metal on metal.  Once it is in gear, it accelerates as normal, and there are no other sounds.  This will only happen after the truck has warmed up 10+ min and does not happen if I decelerate less than 18-20 mph. It does not happen as often if I use the brakes to slow down. Also if I come to a complete stop it does not happen and will only happen if the truck is already in motion above 10mph or so.

I took it to the local GM dealer yesterday, and they said they were not familiar with the problem, but it is definitely not right.  The dealer talked with GM tech support, and GM said they have heard of the problem but did not have a solution.  GM said to take out the transmission and inspect for any visual issues.  If no visual issues could be found, then they would replace the transmission.  Has anyone else experienced this problem?  Any advice moving forward?

Side note- This truck was one of the first sold in our area of the 2019 body styles.  I got it in august of 2018.  It had the leaking back window issue, and they replaced the window after a 2-3 month delay getting the part in and trying to fix it with sealant.

Thank you in advance for your help.

I too have a 2019 Denali with the 10 speed, I have notice a loud bang when I have limitted traction on we pavment when starting off. I feel the noise is coming from the rear end rather than the transmission. It only happens under rare conditions, so it would be Hoothoot⁵²⑩ difficult to replicate at the dealership.

redwngr · January 8, 2022

On 1/6/2022 at 12:27 PM, John Lock said:

I too have a 2019 Denali with the 10 speed, I have notice a loud bang when I have limitted traction on we pavment when starting off. I feel the noise is coming from the rear end rather than the transmission. It only happens under rare conditions, so it would be Hoothoot⁵²⑩ difficult to replicate at the dealership.

Your situation is likely the G80 locking diff engaging.