2021 Tahoe HC Transmission failure @600miles

[TAHOEpeful]

Bought end of July, drove lightly due to break in period. Wife was driving and it began revving high and cut power, slowed down,, and CEL came on. She was able to drive it home. We let it sit over night thinking it was a fluke. I hadn't experienced it so I tried the next day to drive it and it did the same thing to me. Took it home and tried to reverse in the driveway but got stuck in the middle of the street because reverse stopped working. had to drive it to the dealership because they weren't able to come pick it up that day and we were leaving for vacation. Dealer initially told us the transmission needed to be replaced! Needless to say my wife and I were EXTREMELY upset. A few days later, we were told it was a valve body in the trans and they ordered one from GM. When it FINALLY came, it apparently wouldn't program. [emoji2363] Waiting on new valve body and HOPING it works. Sorry for the wall of text, just had to vent!

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[ebelp]

Wow, this is terrifying. Please keep us updated on how long it takes the dealer to get it all fixed and back to you.

 

[TAHOEpeful]

Yes, I definitely will! I'm hoping to hear something ASAP, really missing the ride. GM did a great job on the restyle.

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[2010gmcyukon]

Wow. Yeah I'd be pissed.

 

[OR VietVet]

Apparently any restyle they did on the trans was not so good. If they did not do a restyle on that trans, then they should have parts readily available. I HATE dealing with dealers. I have actually had good transactions with many dealers but then the bad one ruins it for me.

The bad ones give you the run around and just say what they think you want to hear and have excuses at the ready from their "Dealer Excuse Book".

 

[TAHOEpeful]

Wow. Yeah I'd be pissed.

You have no idea, lol. Luckily my wife has an extremely calm demeanor, which counterbalances my anger. Our Tahoe is only the second one the dealer has sold in our area, So I cut them a bit of slack, considering that, and the fact it's a brand new everything model

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[TAHOEpeful]

Apparently any restyle they did on the trans was not so good. If they did not do a restyle on that trans, then they should have parts readily available. I HATE dealing with dealers. I have actually had good transactions with many dealers but then the bad one ruins it for me.

The bad ones give you the run around and just say what they think you want to hear and have excuses at the ready from their "Dealer Excuse Book".

I absolutely agree, luckily this dealer is an expert in selling, and working on vettes, so there is a degree of professionalism from them and a degree of trust from our end [emoji1417]

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[OR VietVet]

I ran shops and was in the auto repair industry for close to 40 years. I told people all the time that if you find a dealer or shop you like, stick with them. The grass isn't always greener elsewhere.

 

[B520044]

I'll be watching this thread. Just had my transmission "reprogrammed" on Friday per TSB 16-NA-019. Which I find odd because that TSB appears to be for model years 2016 - 2017, but that's what it shows on service report. Of course, I have no clue how TSBs work..

Below are some other items from Fridays service. They were able to fix my park assist by reprogramming the
PACM.

 

[TAHOEpeful]

I ran shops and was in the auto repair industry for close to 40 years. I told people all the time that if you find a dealer or shop you like, stick with them. The grass isn't always greener elsewhere.

Sound advice from an expert! Could not agree more, had an issue with a couple dealers by me, years ago, and it's kept me from ever purchasing from them again.

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[TAHOEpeful]

I'll be watching this thread. Just had my transmission "reprogrammed" on Friday per TSB 16-NA-019. Which I find odd because that TSB appears to be for model years 2016 - 2017, but that's what it shows on service report. Of course, I have no clue how TSBs work..
View attachment 256856

Below are some other items from Fridays service. They were able to fix my park assist by reprogramming the
PACM.
View attachment 256862

That's odd, I'm hoping there's no other issues with this car ![emoji2363]

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[Fireman591]

I remember when this had happening to an entire new series of Chevy Silverados decades ago. My Dad who worked at GM Powertrain and was a reliability engineer and metallurgist . He flew down to the plant that made the control modules for the transmission. He discovered one of the employees was not changing drill bits once they got dull in order to save time. The dull drill bit was producing small metal shavings instead of large curly ones. Those metal shavings made their way into the control module and stopped the vehicles dead in their tracks multiple times on multiple vehicles. Needless to say it was a big deal but a very easy fix. Hopefully GM can solve this issue asap.

 

[TAHOEpeful]

I remember when this had happening to an entire new series of Chevy Silverados decades ago. My Dad who worked at GM Powertrain and was a reliability engineer and metallurgist . He flew down to the plant that made the control modules for the transmission. He discovered one of the employees was not changing drill bits once they got dull in order to save time. The dull drill bit was producing small metal shavings instead of large curly ones. Those metal shavings made their way into the control module and stopped the vehicles dead in their tracks multiple times on multiple vehicles. Needless to say it was a big deal but a very easy fix. Hopefully GM can solve this issue asap.

WOW, that's both mind-blowing, and incredible! Mind blowing the fact that somebody could be that lazy and cause so many problems. Incredible that your dad was able to pinpoint the source from so many possible sources! That's badass! [emoji1434] I imagine your dad's response to the person responsible was like the uncle from home alone. [emoji23] Look what you did you little jerk! although I bet it was a lot more vulgar.

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[Fireman591]

WOW, that's both mind-blowing, and incredible! Mind blowing the fact that somebody could be that lazy and cause so many problems. Incredible that your dad was able to pinpoint the source from so many possible sources! That's badass! [emoji1434] I imagine your dad's response to the person responsible was like the uncle from home alone. [emoji23] Look what you did you little jerk! although I bet it was a lot more vulgar.

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If my memory serves I remember him telling me it was a training issue. The employee running the machine did not understand that smaller shavings could have dire effects on the transmission operation. It was a good catch and my Dad's early days with GM making pinion gears paid off LOL

 

[B520044]

WOW, that's both mind-blowing, and incredible! Mind blowing the fact that somebody could be that lazy and cause so many problems. Incredible that your dad was able to pinpoint the source from so many possible sources! That's badass! [emoji1434] I imagine your dad's response to the person responsible was like the uncle from home alone. [emoji23] Look what you did you little jerk! although I bet it was a lot more vulgar.

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Haha, I'm thinking mine was built on a Friday afternoon with Covid-19 temporary workers....

 

[TAHOEpeful]

Haha, I'm thinking mine was built on a Friday afternoon with Covid-19 temporary workers....

Lol you and me both! [emoji2363]

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[TAHOEpeful]

Update: finally got the Tahoe back with 653 MI after their test drive. Service advisor gave us a warning before handing the keys over. He said that the one two shift is going to be really hard for a little while, until everything settles, and the trans "relearns" how to shift again. I found that a bit odd, so I asked him why. he stated because it's a brand new electronic valve body and the transmission was completely flushed of fluid and refilled with "better" fluid. He said he was told by the troubleshooters that it is normal. Not sure I completely agree with that because we got the car with 20 miles on it, and it ran just fine, until it didn't. [emoji2363]

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[Fireman591]

Update: finally got the Tahoe back with 653 MI after their test drive. Service advisor gave us a warning before handing the keys over. He said that the one two shift is going to be really hard for a little while, until everything settles, and the trans "relearns" how to shift again. I found that a bit odd, so I asked him why. he stated because it's a brand new electronic valve body and the transmission was completely flushed of fluid and refilled with "better" fluid. He said he was told by the troubleshooters that it is normal. Not sure I completely agree with that because we got the car with 20 miles on it, and it ran just fine, until it didn't. [emoji2363]

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That is great news. Keep us posted on how it works out.

 

[CMoore711]

Update: finally got the Tahoe back with 653 MI after their test drive. Service advisor gave us a warning before handing the keys over. He said that the one two shift is going to be really hard for a little while, until everything settles, and the trans "relearns" how to shift again. I found that a bit odd, so I asked him why. he stated because it's a brand new electronic valve body and the transmission was completely flushed of fluid and refilled with "better" fluid. He said he was told by the troubleshooters that it is normal. Not sure I completely agree with that because we got the car with 20 miles on it, and it ran just fine, until it didn't. [emoji2363]

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No, you’re absolutely right. 100% of the time my gut and just generally “passing the smell” test has been more accurate than whatever reasoning the service advisers are going to feed you...

I would just continue to drive it as they have directed and probably wouldn’t be a bad idea to check your trans fluid levels every so many miles. If after a full tank of gas that 1-2 shift is still “hard”. It’d be taking it back...

 

[OR VietVet]

Update: finally got the Tahoe back with 653 MI after their test drive. Service advisor gave us a warning before handing the keys over. He said that the one two shift is going to be really hard for a little while, until everything settles, and the trans "relearns" how to shift again. I found that a bit odd, so I asked him why. he stated because it's a brand new electronic valve body and the transmission was completely flushed of fluid and refilled with "better" fluid. He said he was told by the troubleshooters that it is normal. Not sure I completely agree with that because we got the car with 20 miles on it, and it ran just fine, until it didn't. [emoji2363]

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It was years ago but I have heard of a fresh trans or a rebuilt trans or even when a valve body is replaced, that there is a relearn process. IMO, that should be not happening now but what the hell do I know! I have heard the same thing when ECM had been replaced. The theory is that the relearn process is needed to help adapt to the way it is driven because different drivers drive differently. I have experienced that myself.