Transmission Issues

[pigphart]

Hello,

I just purchased a used 2016 Sierra SLT Texas Edition that has 34k miles. Its in beautiful condition like new actually but the transmission is dropping from 2nd to 1st extraordinarily hard. I slow down to come to a stop it hesitates and bangs into gear, I accelerate it hesitates then takes off in low gear fast then shifts hard into 2nd and 3rd gear. I really need help diagnosing this issue so I can recreate it at the dealer to get it fixed. I have read almost all the articles on the issue and no one has a fix, only complaints. IS there a fix to this issue? I love my truck and waited 3 years to buy it and now I have issues with it? IM heart broken.  Please help me figure out how to resolve this issue. I have an extended warranty to service it anywhere it can be fixed.

 

Thank you very much

 

P Archer 

[diyer2]

Did you test drive it?

What are your state laws as far as returning it?

Tune it?

 

[pigphart]

I did test it and in both cases it was warm. But when we had cold weather it began and hasn't stopped. I did return it for service but they were unable to recreate the issue go figure. I have heard that the computer can be flashed to a different version? That's not economical? I wouldn't care if I lost a few mpg to stop the banging into gear and t hasnk you for your reply. I'm in Southern California Burbank Ca

[diyer2]

Make a tech or the service manager ride with you until it acts up.

[pigphart]

good Idea thank you.  Does anyone know if there is a fix via the software controlling the transmission?  I have read that there is a flash available to alter the software eliminating the chatter but thus making it get less gas mileage but its a truck I expect to get not so great gas mileage?

 

[Crstfr]

52 minutes ago, pigphart said:

good Idea thank you.  Does anyone know if there is a fix via the software controlling the transmission?  I have read that there is a flash available to alter the software eliminating the chatter but thus making it get less gas mileage but its a truck I expect to get not so great gas mileage?

 

yes~... i just got my back today for the same issue... 1-2 / 2-1 clunk... and also hesitation between 50-60.   to fix the clunk... which i think it did.. i drove it at lunch..  .. was a tpm/ecm update for both...   drives pretty different.. i'll know more in a few days of driving.

Edited March 6, 2018 by Crstfr

[pigphart]

Outstanding thank you so much. I will offer this as a fix at the deaslers.........I did test it and in both cases it was warm. But when we had cold weather it began and hasn't stopped. I did return it for service but they were unable to recreate the issue go figure. I have heard that the computer can be flashed to a different version? That's not economical? I wouldn't care if I lost a few mpg to stop the banging into gear and t hasnk you for your reply. I'm in Southern California Burbank Ca

[pigphart]

Thank you so much. I will report this to my dealer as a fix. 

[SippiSierra]

6 minutes ago, pigphart said:

Thank you so much. I will report this to my dealer as a fix. 

Let me know how it goes, I am trying to nail down a fix as well. 

[Crstfr]

1 hour ago, pigphart said:

Outstanding thank you so much. I will offer this as a fix at the deaslers.........I did test it and in both cases it was warm. But when we had cold weather it began and hasn't stopped. I did return it for service but they were unable to recreate the issue go figure. I have heard that the computer can be flashed to a different version? That's not economical? I wouldn't care if I lost a few mpg to stop the banging into gear and t hasnk you for your reply. I'm in Southern California Burbank Ca

yeah mine always happens after the truck sat.. like over night.. or in the garage at work.. . even happen in stop and go traffic... give a little gas... clunk~.. you could hear it, and it would push the truck forward some.

[Crstfr]

i'll try and get the numbers that they used for the fix.

[pigphart]

wonderful thank you so much.

[JacobC1983]

6 speed or 8 speed?

[pigphart]

8 speed.

 

 

 

 

 

 

I did test it and in both cases it was warm. But when we had cold weather it began and hasn't stopped. I did return it for service but they were unable to recreate the issue go figure. I have heard that the computer can be flashed to a different version? That's not economical? I wouldn't care if I lost a few mpg to stop the banging into gear and t hasnk you for your reply. I'm in Southern California Burbank Ca

[pigphart]

On 3/6/2018 at 11:29 AM, Crstfr said:

yes~... i just got my back today for the same issue... 1-2 / 2-1 clunk... and also hesitation between 50-60.   to fix the clunk... which i think it did.. i drove it at lunch..  .. was a tpm/ecm update for both...   drives pretty different.. i'll know more in a few days of driving.

How is your truck doing after the flash update?