Valve Body Replacement - 2023 Silverado Custom Trail Boss

Bikerjon · March 1, 2025

6 minutes ago, kyle clayson said:

Hi All,

I just recently joined the club. I have a 22 5.3L V8 trail boss 86k miles(out of warranty ) was running great prior.Truck gears started slipping and was able to get it home. Started the next day and check engine light came on and no reverse. Was able to get it to the dealership with the reduced engine power warning. I dropped it off Friday 2/21 and was immediately diagnosed with the bad valve body issue/code. Service was very vague with me at first and gave me 2 options Valve body replacement with an estimate of $3100.00 or a full transmission of $8,000.00. I went with the valve body replacement and he said he would order the parts. I called this past week just for an update and asked about parts and then they alluded that they were on backorder from GM not another dealership and he thought he mentioned that. There is no way to track the parts? No loaners available I rely on my truck a lot for work and transporting my family of 4 around. Not very optimistic after reading these. Has anyone else experienced the brevity when asking for answers? Has anyone else had to pay for this out of pocket? Im expecting the worst and hoping for the best but not really sure where to go from here other than wait.

Welcome to the forum. Ahhh have you thoroughly read through this thread? This has been a known problem with GM trucks for years. I would contact GM customer Service first and tell them you expect them to fix your truck for free. Parts and labor (they know that hundreds or maybe thousands of these valve bodies have failed). Next contact NHTSA and open a case with them also contact the Better Business Bureau. GM tends to respond quickly when the BBB gets a complaint. This may sound time consuming and a hassle but it may save you $3100.00 and months of waiting time. GM better fix your defective valve body for free.

66ss3964spd · March 1, 2025

I have to guess that you're not going to get much relief on the cost to repair, Kyle. Your truck is significantly out of warranty at this point, and while the valve body failures are wide spread and well documented by owners, GM has not acknowledged the problem in the form of a recall.

That, of course, doesn't mean you shouldn't try by following the leads Jon mentioned above. GM might authorize a good will repair. You might also try to negotiate the repair cost with the dealer. Someone on this thread posted the part number of the new valve body that was installed in their truck and when I googled that PN I saw listings that were for $1000.00, sometimes less. I've read the time to replace is maybe 4 hours, X whatever the dealer's shop rate is. Even if the shop rate is 200/Hr, that's 800. + 1000 for the VB that's 1800. Have to factor in the fluid, filter, gasket, and maybe some other small bits, but no way those extras will add up to an extra 1000.00.

truck girl · March 1, 2025

I'm sorry you are experiencing this failure. Ours was repaired in October, also a 22. I would not pay out of pocket. You are only a few thousand miles over the drivetrain warranty. This is a known problem by GM. I'm guessing in the hundred thousands. Call the GM service hotline to let them know you expect this to be covered under warranty and you will take legal action if not. If necessary get a lawyer.

66ss3964spd · March 1, 2025

With respect, Kyle's truck is not only a few thousand miles over the 60K DT warranty, it is 26 thousand miles over. Until GM, or the NHTSA, formally acknowledges the problem GM has no legal/financial liability here. Not fair under the circumstances, but is reality.

Depending on what state, and given the estimated 3100 repair bill, the only legal avenue might be small claims court, and typically lawyers are not permitted.

Again, I'm not suggesting do nothing, just trying to help set expectations.

JustSomeDude · March 1, 2025

In a few different forums, it seems like the experience varies from person to person, and dealer to dealer. But one common thread seems to be that the dealers locally tend to be more concerned with it because they're the front line. GM as a company is not making it right him putting their dealerships in a good position.

I was told that mine would take up to 3 or 4 weeks. And then when I had one in a couple of days the service person at the dealership seemed completely floored. Once I started learning more about this problem, I understood why she was so surprised that it was in that quickly.

truck girl · March 1, 2025

Even though our truck was under warranty GM agreed to extend the warranty on the valve body past the 60,000 miles. GM did recall over half million diesel trucks last year with the same problem. They agreed to reimburse those that weren't under warranty and paid out of pocket. Unfortunately the recall only does a software update to alert the driver before the VB fails so it doesn't lock up. So that's disappointing but it does show for a known problem they were willing to fix/reimburse the owners after the warranty period as well as their willingness to extend our drivetrain warranty.

I contacted the CEO of GMC, Mary Barra as well as all the board members. I received a call within 2 hours after my email and our truck was fixed within a week after being told it could be months. So I always suggest being proactive in a situation such as this. We were told no over reimbursing us many times until I reached out this way.

But that's just me. I hate to see injustice and it makes me angry when corporations don't do the right thing. I image that a class action suit will be filed at some point since this affects millions of GMC trucks.

JustSomeDude · March 1, 2025

I operate a business and would never claim that we never make any mistakes. We do our best to avoid them but when a mistake happens we own up to them and do what's necessary to correct it.

It is a shame that that is not appear to be happening for a lot of people. Truck Girl is taking these steps and it sucks that we even have to hassle with that stuff on a $60k+ truck.

Taking care of the valve body is the bare minimum that I would expect they would do. My bigger concern is that if the valve body is going bad, what is happening to the transmission inside?

My previous Silverado had 200,000 mi on it and I never had a single transmission or engine issue so I was very disappointed to have this transmission issue on this truck.

66ss3964spd · March 1, 2025

The diesel truck transmission failures are not the same as the failure that so many of us have, or will, experience, and it appears to be with an entirely different transmission - the 8 speed.

Consider the numbers, there have to be millions of these 10 speed equipped trucks/SUV's out in the wild now since that trans was introduced over 5 years ago. Assume there are 2 million of them (probably conservative). Further assume the dealers bill GM 1500.00 (also probably conservative) for each one they repair under warranty. 3 billion dollars. I seriously doubt they'd start replacing all the VB's proactively since not all of them are failing.

IMO, the most likely scenario is, if a recall, or even a CA suit for the 10 speed VB issue does ever happen, GM will "settle" by extending the PT warranty, or maybe just the transmission warranty, and offer reimbursement to any owner who had to pay out of pocket for a repair.

kyle clayson · March 3, 2025

I appreciate everyones feedback. Im not expecting much but I have set formal complaints with GM and NHTSA. My guess is Im still going to pay for out of pocket but maybe my complaints will get it done quicker. More agitated with the dealership that was willing to take $8,000.00 if I had agreed to go that route with little transparency. Doesn't seem ethical to me but we will see what happens. I will be asking for a formal quote as they havent given me one. I will keep everyone updated. Thanks for everyones input.

GNP TJR · March 4, 2025

I have a 2023 gmc AT4 w/ 3.0L diesel. Had several weird shifts over the 40,000 miles I have on it. First time in shop they said it was the DEF system, within a week the transmission shifting became much worse. Engine light came on and truck went into “limp mode”. Feels like it’s in 3 or 4th gear all the time, will not shift. I can for about 50mph max before my rpm’s get too high for comfort. Plus take off is slow because it has no torque.
GM Dealer says same thing - Bad Valve Body in the tranny.
national back order, said could take several months and has no idea when it might arrive. After reading blogs (THANK YOU ALL) I’m going to see if entire tranny can be authorized and will call GM if needed. This is crazy for a truck that cost over 70k!
if that doesn’t work will trade for Tundra…

SCOOTER1951 · March 4, 2025

On 1/16/2024 at 11:57 PM, Michael Lung said:

Wanted to reach out to the forum to see if any one has needed a valve body replaced for their 2023 Silverado? I'm currently in the process waiting on the part to show up at the dealer, going on for about a month now.

I bought the truck new in Jan 2023, 5.3L Custom Trail Boss, and everything was fine till about 15K miles when I noticed a very hard downshift when accelerating, anywhere between 30-70mph. Usually the shifts were very violent, sometimes even turning my cruise control off because the truck chirped the tires and broke traction. Eventually took the truck to the dealer late November 2023 and they tried the software approach, which I understand, but no dice on that being the fix. I did some self-diagnosing and realized the hard shifts only started happening around 140 degrees on the transmission gauge and somewhere between 6-8 gear. Was able to get the truck back in to the dealer mid-Dec 2023 due to their availability, and was diagnosed with the valve body needing to be replaced on the transmission, and now stuck waiting for the part.

Per the Service Advisor, there is already a new part number and a new manufacturer for the valve bodies, so perhaps GM is addressing a somewhat of an issue with the original valve body? Now the weird part is apparently GM is beholden to this manufacturer on when they ship out these valve bodies as parts orders, only receiving shipment once the local region has hit a certain quota, per the Service Advisor. I mean, at least GM has me in a comparable rental, but I sure would like to be back in my truck at this point. Curious if any forum member has had a similar issue in getting a new valve body for these 10-speeds on the '23 Silverado?

Michael, did U ever get it fixed, if so, how long was your wait?

I've been waiting 2mos so far...NO eta available!

JustSomeDude · March 4, 2025

5 hours ago, GNP TJR said:

I have a 2023 gmc AT4 w/ 3.0L diesel. Had several weird shifts over the 40,000 miles I have on it. First time in shop they said it was the DEF system, within a week the transmission shifting became much worse. Engine light came on and truck went into “limp mode”. Feels like it’s in 3 or 4th gear all the time, will not shift. I can for about 50mph max before my rpm’s get too high for comfort. Plus take off is slow because it has no torque.
GM Dealer says same thing - Bad Valve Body in the tranny.
national back order, said could take several months and has no idea when it might arrive. After reading blogs (THANK YOU ALL) I’m going to see if entire tranny can be authorized and will call GM if needed. This is crazy for a truck that cost over 70k!
if that doesn’t work will trade for Tundra…

The same feelings are shared here. So much money for a truck to have this level of problems. My previous truck ('06 Silverado) had 200K miles with zero engine or transmission problems, so brand loyalty was a legit factor in my purchase of my first new vehicle ever. But the way GM is handling (or more accurately NOT handling this) is actively working against and eroding that brand loyalty.

Asolomon · March 5, 2025

On 1/29/2025 at 10:01 AM, Asolomon said:

Update, has been 57 days since I dropped my vehicle off at the dealership and still no word or ETA and when I asked about a transmission replacement last week they flat out said no GM wants us to replace the part. So I guess the wait continues

Finally got the call my valve body came in! I did open a case with GM about 2 weeks ago and they managed to get one to my dealership. They cant get to it until next Monday the 9th but will post another update on how the truck is feeling and part numbers. Actually got some relief after its been sitting there for roughly 90 days.

Edited March 5, 2025 by Asolomon
Fix number

SilveradoRST · March 5, 2025

19 minutes ago, Asolomon said:

Finally got the call my valve body came in! I did open a case with GM about 2 weeks ago and they managed to get one to my dealership. They cant get to it until next Monday the 9th but will post another update on how the truck is feeling and part numbers. Actually got some relief after it’s been sitting there for roughly 90 days.

Oh man, 90 days. That’s rough. Glad you’re getting it back.

GMCustomerService · March 5, 2025

On 3/4/2025 at 6:46 AM, GNP TJR said:

I have a 2023 gmc AT4 w/ 3.0L diesel. Had several weird shifts over the 40,000 miles I have on it. First time in shop they said it was the DEF system, within a week the transmission shifting became much worse. Engine light came on and truck went into “limp mode”. Feels like it’s in 3 or 4th gear all the time, will not shift. I can for about 50mph max before my rpm’s get too high for comfort. Plus take off is slow because it has no torque.
GM Dealer says same thing - Bad Valve Body in the tranny.
national back order, said could take several months and has no idea when it might arrive. After reading blogs (THANK YOU ALL) I’m going to see if entire tranny can be authorized and will call GM if needed. This is crazy for a truck that cost over 70k!
if that doesn’t work will trade for Tundra…

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