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New 2025 HD gas 300 miles needs VALVE BODY

dddavel

By dddavel
in 6.6L Gas V8 (L8T)

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dddavel New Member

dddavel

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My brand new 2025 HD gas with 300 miles on it needs a valve body. Sitting at dealer now for who knows how long. Thought they had the problem fixed for the 2025's but not mine!

GMCustomerService Senior Enthusiast

GMCustomerService

Posted
Posted
16 hours ago, dddavel said:

My brand new 2025 HD gas with 300 miles on it needs a valve body. Sitting at dealer now for who knows how long. Thought they had the problem fixed for the 2025's but not mine!

We know how upsetting part delays are, especially with such a new vehicle, and we would like to create a case on your behalf in our system and assist. Please email us at [email protected] with your full VIN and dealership information. We look forward to hearing from you. By sending us a message, you consent to the information you provide being monitored and recorded by GM or those acting on GM’s behalf, subject to the GM Privacy Statement: https://www.gm.com/privacy-statement.

dddavel New Member

dddavel

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It was randomly getting a check engine light and going into limp mode (5th gear). Showed codes P0964 and P0700.

Did it 4 times in the 325 miles I got to put on it.

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Chuck FB Enthusiast

Chuck FB

Posted
Posted
14 hours ago, dddavel said:

It was randomly getting a check engine light and going into limp mode (5th gear). Showed codes P0964 and P0700.

Did it 4 times in the 325 miles I got to put on it.

I highly doubt wear is the issue !, assuming they even will look at the valve body and it may not even be easy to figure out what is wrong unless those codes zero in on something, it would not surprise me if there was a possible machining hickup or one of the components installed into the valve body isn't sealing properly and your loosing oil pressure or one of the solenoids isn't functioning correctly. All it would take is one item messed up and it would go into fail mode. Things like this do happen and I had something similar happen to a chev pickup years ago in its trans early on and they went through it, found out what was messed up from the factory ( a cut oring of all simple things ) and replaced any damaged components because of the pressure loss and I was good to go ... frustrating for sure but it got repaired properly and life went on.

dddavel New Member

dddavel

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Posted (edited)

They said they took out the valve body and checked ohm's readings and it was way wrong from what it should be. Today they told me it's on backorder with no date showing.

Edited by dddavel
No F-bdy Bs Enthusiast

No F-bdy Bs

Posted
Posted

Well, at least you get a 10yr,150k warranty now. 

 

 

Fwiw, I have a 25' gasser, and the first major issue I get, I'm trading it in. 

I refuse to dick around with issues Gm KNEW to exist when they sold it to me. 

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Chevyfan3 Enthusiast

Chevyfan3

Posted
Posted
On 5/7/2025 at 2:22 AM, dddavel said:

My brand new 2025 HD gas with 300 miles on it needs a valve body. Sitting at dealer now for who knows how long. Thought they had the problem fixed for the 2025's but not mine!

 

I don't think the problem will get fixed until they redesign the transmission. They have let out go on for 5 years now, it must be an inherent flaw with the 10L or they just don't care to fix it. There have been 25's popping up on the forums with valvebody issues and my buddy who is a tech has seen a few as well. The year he sees the most of are the 24's so far.  As far as parts availability goes it's a crapshoot and something GM really needs to get in check, having trucks wait weeks or months for a simple part of ridiculous.

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No F-bdy Bs Enthusiast

No F-bdy Bs

Posted
Posted

If you have the Allison 10spd, I'd hedge my bets, by claiming it "felt like the rear tires locked up when I was going down the highway!" just to get the warranty. 

OS RR Enthusiast

OS RR

Posted
Posted
On 5/14/2025 at 9:39 PM, Chevyfan3 said:

 

I don't think the problem will get fixed until they redesign the transmission. They have let out go on for 5 years now, it must be an inherent flaw with the 10L or they just don't care to fix it. There have been 25's popping up on the forums with valvebody issues and my buddy who is a tech has seen a few as well. The year he sees the most of are the 24's so far.  As far as parts availability goes it's a crapshoot and something GM really needs to get in check, having trucks wait weeks or months for a simple part of ridiculous.

 

Diesel or gas? From what I've seen it seems to lean heavier towards the diesel side.

 

 

No F-bdy Bs Enthusiast

No F-bdy Bs

Posted
Posted
20 hours ago, OS RR said:

 

Diesel or gas? From what I've seen it seems to lean heavier towards the diesel side.

 

 

Seems to be that way, but I wonder if that's due to the sheer #s of diesels Vs gas? 

Also, diesels being more likely used to tow heavier. Probably just speeds up the decline/wear. 

 

From what I gather, it's just a flawed design overall. 

  • 3 weeks later...
dddavel New Member

dddavel

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My 2025 Gasser has been sitting 4 weeks now, they still keep saying backorder. I see more reports online of 2025's having this problem.

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Chevyfan3 Enthusiast

Chevyfan3

Posted
Posted
On 5/16/2025 at 11:10 AM, OS RR said:

 

Diesel or gas? From what I've seen it seems to lean heavier towards the diesel side.

 

 

He's seeing more diesel trucks with the issue so far but gassers here and there as well. Dmax trucks are more popular in my area so that could be why he is seeing more of those vs the gassers as well.

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