Transmission gear won’t be limited unless truck is in danger of rear wheel lockup, better reduced than out of control due to the rear wheels locked up.

 

I reckon but at what point -10000 miles is it occurring? 40k? 50k? 100k? They have to know that already. And does that mean 5th gear only (45-50 mph) until they find a fix? Not acceptable. We will be able to clear the CEL and codes with our scanners? My guess is no, we won't. We will wait an see if this is going to be a widespread issue like the twins or Tacomas.

 

I was reading through the documents on the NTHSA web site and only 1 percent of vehicles are expected to have an issue. The trans will shift 1 thru 5, not just 5th. I’ve heard most issues have been over 80,000 miles. Owner letters will go out December 9th

 

It happened in my 2020 at 36k miles. Freeway speed pulling a 5th wheel trailer. Momentary rear wheel lockup 3 or 4 times before we got to a place to stop. Scared the crap out of us, we thought it was the trailer at first since the truck was to new to have a problem like this. Ended up replacing the transmission under warranty.
About 2K miles more the transfer case needed to be replaced. It was full of shavings - I think it was from when the transmission crapped out.
This fix is a joke but better to be limited to 5th gear than stranded.

 

Step one is the software up date.

Software update makes it so the valves diagnostics can detect if there is wear in the valve, and is supposed to be able to detect this 10,000 miles before there is enough wear for the shift issue to occur.

If the wear occurs, then the valve gets changed.
If the wear doesn't occur, no need to open the transmission.

 

Where did you find this, red? Right now the recall says there is no remedy. I’ll assume the valve will need to be replaced at some point on all of our vehicles.

 

It was in a couple of the press articles -- but not all of them.

Stories say to wait for a letter before contacting dealer -- and they don't go out until early December.
(Of course that can change too)


This is from the GMAuthority website:
(I deleted the pictures)

Chevy Silverado, Tahoe And Suburban Recalled For Rear Wheel Lock-Up Due To Transmission Valve Failure
By Rhian Hunt
November 14, 2024 3:07 pm


GM has issued an extensive recall that includes the 2020 through 2022 Chevy Silverado pickup truck as well as the 2021 Chevy Tahoe and 2021 Chevy Suburban SUVs and a range of other models, for units that have defective transmission control module software that can increase the risk of a crash.
Notably, all affected units covered by GM Safety Recall number N242454440 are equipped with Duramax diesel engines. Vehicles from the same nameplates and model years that are equipped with gasoline engines use a different transmission and are not affected.

The problem: affected diesel-motivated Chevy Silverado, Chevy Tahoe and Chevy Suburban units are subject to a condition in which the transmission control module software is unable to detect problems with the pressure in the transmission, causing the control valve to fail.

The hazards: the specific cause of failure is that the transmission control valve may wear improperly over time. The valve will gradually lose pressure, making shifting harsher. Eventually, this will lead to failure of the valve. Factory transmission control valve software is unable to detect the decreasing valve pressure.
If the transmission control valve of affected Chevy Silverado, Tahoe or Suburban vehicles fails, the rear wheels may lock up while the truck or SUV is in motion. Depending on the situation, this rear-wheel lockup – which is only momentary – can increase the risk of a crash or other accident.

This failure and rear-wheel lockup occurs specifically when the automatic transmission downshifts from eighth gear.

The fix: dealerships are instructed to install new transmission control module software. Notably, the new software is capable of detecting excess valve wear 10,000 miles prior to rear-wheel lockup.
Once valve wear is detected, the software will prevent the transmission from shifting above fifth gear, ensuring the eighth-gear lockup cannot occur. The instrument panel will also correctly display “reduced propulsion” and “service engine” warnings at that time. GM will release a special coverage program to repair transmissions affected by a defective control valve, as detected by the newly installed software. However, at the time of this writing, no parts are available for the transmission fix.
Also effective immediately is a stop-delivery order on all affected Chevy Silverado, Suburban, and Tahoe units. Any such units that are Certified Used by The General are immediately decertified as well and are removed from the GM Certified Pre-Owned (CPO) program.

Affected components: transmission control module software.
Affected vehicles:

• 2020 Chevy Silverado 1500
• 2021 Chevy Silverado 1500
• 2022 Chevy Silverado 1500
• 2020 Chevy Silverado HD
• 2021 Chevy Silverado HD
• 2021 Chevy Suburban
• 2021 Chevy Tahoe
• 2020 GMC Sierra 1500
• 2021 GMC Sierra 1500
• 2022 GMC Sierra 1500
• 2020 GMC Sierra HD
• 2021 GMC Sierra HD
• 2021 GMC Yukon
• 2021 GMC Yukon XL
• 2021 Cadillac Escalade
• 2021 Cadillac Escalade ESV

Number of affected vehicles: the Chevy Silverado pickup truck has the largest population of affected vehicles in the recall, with 66,897 Chevy Silverado 1500 and 166,541 Chevy Silverado HD trucks involved. The number of Chevy Suburban units being recalled is 2,525, while 3,858 Chevy Tahoe SUVs are also included.
In total, 461,839 vehicles across the Chevrolet, GMC, and Cadillac brands are affected by the problem and subject to the recall in the United States. Another 52,220 units are involved in Canada as well.

Owners should: wait for GM notification letters, which are expected to be mailed on or near Monday, December 9th, 2024 to all owners of record for affected Chevy Silverado, Tahoe, and Suburban vehicles. These letters should contain instructions for further actions to deal with the recall. Recipients should read the letters carefully for special information related to the matter.

Inspection and repair of the involved vehicles will be carried out free of charge to the owner by GM service departments. Furthermore, courtesy transportation may be available to owners of affected vehicles until the fix is applied, provided that the vehicle in question is still in warranty for the particular issue involved.
Owners with further questions about the recall and related issues can contact Chevrolet customer service at the following toll-free telephone number, citing the recall number as necessary:
Contacts:

• GM recall number: N242454440
• Chevy Customer Service: 1-800-222-1020

 

Thanks, redwngr. If the lockup happens at 8th gear downshift, why limit it to 5th and not 7th? At least the truck would be more useable. Also, if hard downshifting is a symptom, recommend the software download after that happens. As it stands now, once the download detects this fault, you could be without a good transmission until they get enough parts in stock. We’ve all seen how responsive GM is about that with previous issues. I’ll not lose sleep over this one. And not have a dealer install that software update until a fix and timeline is announced. I’m currently at approx 57k. If the issue occurs over 80k or 100k, there’s time.

 

Only a guess, but I suspect the delay in installing the software that can do the detection is so that can have more valves on hand, since the revised software is probably going to find valves that are leaking -- but haven't yet had shown the 'temporary lockup' condition.

 

Would a trans tune help remedy this problem?

 

The delay could also just be developing the software. The EV software fix last year took months to develop. It’s entirely possible the letters in December may say you’ll get a second letter when a fix is available

 

At 33k I'm going to put this one in the "I'm not too worried about it file".....

 

At a 1 percent failure rate I don’t think I’ll be too concerned at 80k

 

The 5th gear limit will clear with a key cycle until it detects excessive leakage again.

It's limited to 5th since 6,7 and 8 use the same clutch pack....so the valve that controls it is likely the culprit.

 

I hope GM releases that software update for these trucks soon, I'm in the process of buying a 2020 GMC 2500 Duramax, but the dealer can't sell it to me due to the recall and associated stop-sale order from the NHTSA. I've already sold my old truck so now I'm just playing the waiting game I guess.

 

Found On Road Dead

😈

 

Fix Or Repair Daily

F'n Old Rebuilt Dodge

Garage Mans Companion

 

Oddly enough my dealership has a 23 in the back lot with the failure gm claimed to only effect 20-22 lol

 

The failure still occurs on the new trucks just 23' up has the software in place to detect the issue and place you in derate where the 20-22 didn't have that software thus the recall. Even after the 20-22 get the software recall done the failure can still occur, it just won't create as dangerous of a situation for the driver.

 

For owners that have had this issue, I wonder what other possible symptoms they were also experiencing? I have heard rough/poor up shifts, etc but just going with what I’ve read. I personally have not had any trans/shifting issues at all.

 

I'm so glad we kept our 2003 Silverado 2500 HD Duramax/Allison combo. We only have 153,500 miles on it and did have to change out the injectors at 99,000 miles. GM did a recall on them and would cover it if it was no older than 7 yrs old and 200,000 miles. Ours was 9 yrs old with 99,000 miles so we had to pay for it. Other than that, we have had no issues and it still runs great. 21 to 22 mpg solo and 11-12 when we were towing. Sold our RV, so don't do that anymore.

 

I actually had a notice pop up on my radio display a few weeks ago. Dealer did the software update last week. Waiting to see what happens down the road 2021 duramax 3.0, 47k miles

 

We had some stuttering on light throttle in rush hour stop and go traffic on a hot day pulling 16k 5th wheel. It was very annoying, friend had his Ford do same thing, he takes it out of tow/haul mode in that situation and it seemed to help. I only had it the one time, although at 45-55mph light throttle sometimes gets a bit of stutter.. and one other time we had some weird downshifting after coming down a long grade in Montana... trans temp was 185 (highest I have seen it).

I have Edge CTS3 so I can see what gear I'm in and if the TC is locked or not now. We have Arizona trip in spring so we'll see how it does. I need to check fluid level before trip also...

 

I knew I wasn’t going crazy. I have a 2021 gmc sierra 1500 with this duramax. It all started at the beginning of this year somewhere near >80k miles. I’ve towed like twice with this truck in the 28k mile span that I’ve had it for so I knew I had not messed it up. The transmission slowly started to act funky. I commute like < 20 miles a day, don’t drive aggressively, and suddenly there was stuttering all over the place. At first it was between 2 specific gears only, but it just worsened over time. Now it downshifts super weird when on a decline, no matter what grade. Sometimes you’ll accelerate and the truck hesitates and moves no-where for a split second. Shifting is harsh and jerky at times. I couldn’t honestly believe the trans was gonna fail me way before 100k miles. One day i go do an oil change and mention it to the service guy, and he recommended first doing like a $700 trans fluid flush, to even see if the problem persisted and then move on with diagnosing the trans if it didn’t improve the shifting, ridiculous. Nice truck but I really wanted to trade it for this reason. With this recall, I don’t think I’ll get a good trade in offer anywhere unfortunately.

 

Hopefully you didn’t spend the $700 for the fluid change… just get it fixed under this recall. Should be getting a new valve body eventually (and a fluid change) once they get all the parts… hopefully they have truly figured out what the root cause is and fix it permanently. I think that’s part of the reason for the software monitoring, so they can repair the ones that are the worst/having issues first, as there is over 1/2 a million of them to repair! Damn Furd transmission! 🙃

 

Why are they having to "develop software" to detect this issue when the '23, and newer, trucks supposedly already have it? Are the TCUs so different that they can't use the same f'n code? I agree that this is total BS while they re-engineer the defective valves. Sorta like when it took me 3 months to get a new short block under recall for my '16 Sonata when the engine let go. Hyundai supposedly shifted engine production to Korea and were "running 24 hours a day" to build new short blocks to cover the recall. Why not fix the engine plant in Alabama, where the original engine came from?

Lyle

 

Re-engineering of the defective valves should of already been in place IMO, the way this looks is as if they were going to see how far they could get leaving it as is and leaving owners to hold the bag out of warranty when it failed.

I know 24-up trucks are on the new global b stuff so Im willing to bet the coding is much different on those, now 23' trucks you would think could retro back to the older models.

 

I wonder if the Ford 10 speeds are having this issue as well? We have been led to believe that the Ford and GM 10 speed in the HD trucks are essentially the same. So if the piston wears and causes the fluid to leak is this a manufacturing flaw only present in some or is this a design flaw that when tolerances are stacked along with other factors will occur?

 

It's 150 and 1500 that are the same (and developed by ford)

Each manufacture their own, so there could be differences in manufacturing process.

 

I haven't read about it happening in the 10r40 in the ford HD trucks, but ford valve body is different vs the GM truck if you watch the tear down videos between the 10l and the 10r.

 

I haven't received a letter yet but I checked my VIN# and my 2022 2500HD is under the recall. It said no parts to correct the issue are currently available. The only issue I've encountered was in September while towing our trailer. We were turning it and the truck suddenly went into "Hill Hold" then released. The same thing occurred in early October while I was slowly backing into my parking space. Very unnerving. The issue has not repeated itself. I'll have to keep an eye on it. Otherwise, the transmission shifts as smoothly as always (knock on wood)!