Died at 70mph on I-75

schmit55 · Mar 15, 2026

Our 4k mile 2026 AT4 ultimate almost killed my family yesterday. I accelerated hard merging onto the freeway and heading into a turn the engine shut off, the screen said push to restart and wouldn't work and thankfully i was able to coast to a flat area on the shoulder.

We could have easily crashed and my whole family died.

It screen remained on and would. It would not restart nor could I shift it into neutral. App says engine/transmission service now.

Onstar was not helpful and eventually we left it with the key in it and 7 hours later after dozens of back and forth with onstar they got a tow truck with a dolly for the wheels and it is now at the dealership waiting for them to open tomorrow.

I am very upset about it trying to kill my family.

sohanrd · Mar 15, 2026

6.2 or 5.3?

schmit55 · Mar 15, 2026

sohanrd said:
6.2 or 5.3?

6.2. But I think its the trans

JayceeP · Mar 15, 2026

Yikes! Glad you’re all ok.

BacDoc · Mar 15, 2026

schmit55 said:
Our 4k mile 2026 AT4 ultimate almost killed my family yesterday. I accelerated hard merging onto the freeway and heading into a turn the engine shut off, the screen said push to restart and wouldn't work and thankfully i was able to coast to a flat area on the shoulder.

We could have easily crashed and my whole family died.

It screen remained on and would. It would not restart nor could I shift it into neutral. App says engine/transmission service now.

Onstar was not helpful and eventually we left it with the key in it and 7 hours later after dozens of back and forth with onstar they got a tow truck with a dolly for the wheels and it is now at the dealership waiting for them to open tomorrow.

I am very upset about it trying to kill my family.

You have every right to be upset!

I have posted this before but losing your brand new engine or truck is bad enough but nothing compared to endangering human lives.

The fact that “loss of propulsion” can cause injuries or death is a serious situation that has to be addressed. The fact that a brand new vehicle with the OEM engine has a history of this and the cause is well documented beyond any shadow of doubt is a legal and ethical liability of astronomical proportions!!!!

Thank God you and your family survived but the difference between you and your loved ones seriously injured or dead is the grace of God or luck.

This needs to be fixed and money is not even a fraction of the cost.

So glad you and your family survived!

sohanrd · Mar 15, 2026

schmit55 said:
6.2. But I think its the trans

Could be TCM crash/issue. If the TCM doesnt communicate with ECM well, ECM wont know the current gear and then shuts down the motor for mechanical safety.

mountie · Mar 15, 2026

Again……. I will say….. I am SO GLAD I own a 2005 Yukon…… 180,000 and no issues...
Man-o-man…. The new ones……. Man-o-man…..

Blueinterceptor · Mar 15, 2026

mountie said:
Again……. I will say….. I am SO GLAD I own a 2005 Yukon…… 180,000 and no issues...
Man-o-man…. The new ones……. Man-o-man…..

That’s probably not a helpful commentary

tom3 · Mar 15, 2026

Not much we can say that is helpful at this point. Any type of car trouble on I-75 is dangerous. That's just a disaster!

RST Dana · Mar 15, 2026

schmit55 said:
Our 4k mile 2026 AT4 ultimate almost killed my family yesterday. I accelerated hard merging onto the freeway and heading into a turn the engine shut off, the screen said push to restart and wouldn't work and thankfully i was able to coast to a flat area on the shoulder.

We could have easily crashed and my whole family died.

It screen remained on and would. It would not restart nor could I shift it into neutral. App says engine/transmission service now.

Onstar was not helpful and eventually we left it with the key in it and 7 hours later after dozens of back and forth with onstar they got a tow truck with a dolly for the wheels and it is now at the dealership waiting for them to open tomorrow.

I am very upset about it trying to kill my family.

What state was this event happening? I75 goes south almost to the equator and north near the Arctic circle. I’m in Ohio and would have been happy to help around the Cinci area.

schmit55 · Mar 16, 2026

RST Dana said:
What state was this event happening? I75 goes south almost to the equator and north near the Arctic circle. I’m in Ohio and would have been happy to help around the Cinci area.

Troy Michigan. Just north of Detroit.

mountie · Mar 16, 2026

Blueinterceptor said:
That’s probably not a helpful commentary

I didn’t mean to sound that way…..
The new ones are beautiful ! I was imagining …someone would create an alternative service manual to address all the glitches.
The newer models should be as reliable as the ’99 - ’06 versions.

LSCALADE · Mar 16, 2026

Thats a huge bummer and not good having the family with you. This may be one of the only reasons that I chose to stay with the prior gen since they are not known to have these types of sudden failures and I think I am glad I went that route.

Now the only thing you can do is wait to see what comes out of the replacement but yeah I am from detroit area as well and I know how bad Troy area can be with merging on the free way.

Try the Dixie merge into I75 Norht the ramp is into the fast lane with no room to accelarate, thats one of the worst ramp in the entire lower michigan.

10spds have been having a ton of issues in the 2021-up models. Read up on Nex Gen trans valve body fixes, tons of videos on youtube they describe lock up issues and overal odd behavior due to poor trans control design. A new GM valve body may not at all fix the problem and it could re-occur. If they diagnose it with that I strongly recommend going with Nex Gen parts instead of OEM.

schmit55 · Mar 16, 2026

Is there a case number or something I need to open with onstar to get the dealership to work on this and give me a rental?

mountie · Mar 16, 2026

schmit55 said:
Is there a case number or something I need to open with onstar to get the dealership to work on this and give me a rental?

With only 4K miles on it….. They better take care of you !
If you have any issues with them ….. You can go to another dealer …..

Doubeleive · Mar 16, 2026

schmit55 said:
Is there a case number or something I need to open with onstar to get the dealership to work on this and give me a rental?

first rodeo? just call the dealer where the vehicle is and tell them you need a rental or loaner if they have one.

jfoj · Mar 16, 2026

Sorry to hear about your situation, this should not still be happening, but it unfortunately still is.

Most likely the engine, not the transmission. Based on the fact the engine quit and would not restart and all the 6.2l related problems, the failure is more than likely with the engine. If the engine will not run you cannot get the transmission to shift out of park. Trust me I know this and have added a park release cable to my truck.

You need to fill out a NHTSA Safety Defect report, https://www.nhtsa.gov/report-a-safety-problem

This may not necessarily help you at this point, but GM has expanded the 6.2l investigations, but have yet to include the 2025-2026 model years. Seems there was really no change with the 6.2l build quality after July 2024 as they claim.

How many miles are on the vehicle??

Please update what the dealer finds and confirm you have filled out the NHTSA Safety Defect Report.

schmit55 · Mar 16, 2026

They have it on a lift right now. They say it is an electrical issue.

jfoj · Mar 16, 2026

Keep in mind if the engine actually seized often when you try to restart the engine and itis seized, the fuse for the starter blows and/or the fuse box melts which then needs to be replaced before they determine there is an engine failure unless the tech tried to turn the engine from the front crank bolt. Hopefully it's as simple as an electric problem, but based on history it doesn't seem like it.

jerry455 · Mar 16, 2026

I bought my 2021 Suburban used from Moran Chevrolet, Clinton Twp MI, and any service, they give me a courtesy vehicle. They have been great. Even the PICO test, they were a little backed up and gave me a loaner. Hopefully they give you some details soon.

Died at 70mph on I-75

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