Transmission valve body-no parts to be found

[jensenswanson]

My 2025 Yukon Denali with the 6.2 has been in the shop 5 weeks now awaiting a valve body. It only has 934 miles on it and I couldn't be more disappointed with the way GM has handled this so far. I have now been escalated to the "Parts Delay Department" where they will undoubtedly continue to feed me lines about how much they understand how frustrating this must be and how they are doing everything they can to rectify the situation as soon as possible.

I asked both the dealer and the GM rep if they have heard of the Nextgen kit and if they could use those parts as they appear to be better made and, perhaps even more importantly, are readily available. The answer I got from both was NO.

I also have big car payments to make for a BRAND NEW VEHICLE that has been at the shop way longer than we have had it on the road. Beyond mad and feeling incredibly frustrated.

So much for the theory that the '25 got better parts....

 

[jfoj]

@Staceyr72

Any update or progress with your situation? What was the problem with your vehicle originally? Harsh shifting? P0747?

 

[jfoj]

@Davefan

What were the symptoms of your vehicle that caused you to take it in?

Harsh shifting? P0747? Other?

 

[jfoj]

@jensenswanson

What were the symptoms of your vehicle when you took it in? Harsh shifting, P0747, other?

While GM says no to something lke the NextGen kit, I plan on probably proactively instaling it in my truck. If my truck was tied up for 5 weeks, I would pick it up and probably do the NextGen kit anyway. Does not really matter much as these trucks will likely get the software Recall like the Diesels and the 90,000 Cadillac sedans and Camero's. Just a matter of time. Then if the TCM software recall is released on these gas trucks, GM will likely then extend the valve body Warranty for 15 years - 150,000 miles like the Diesel trucks and the 90,000 Cady's and Cameros.

Anyone who is having valve body probems NEEDS to fill out a NHTSA complaint form, this can be done online. Understand the more complaints, the more likely and sooner the TCM software recall and valve body warranty extension will show up for the gas powered light trucks.

NHTSA Online Complaint Form

 

[jensenswanson]

@jensenswanson

What were the symptoms of your vehicle when you took it in? Harsh shifting, P0747, other?

While GM says no to something lke the NextGen kit, I plan on probably proactively instaling it in my truck. If my truck was tied up for 5 weeks, I would pick it up and probably do the NextGen kit anyway. Does not really matter much as these trucks will likely get the software Recall like the Diesels and the 90,000 Cadillac sedans and Camero's. Just a matter of time. Then if the TCM software recall is released on these gas trucks, GM will likely then extend the valve body Warranty for 15 years - 150,000 miles like the Diesel trucks and the 90,000 Cady's and Cameros.

Anyone who is having valve body probems NEEDS to fill out a NHTSA complaint form, this can be done online. Understand the more complaints, the more likely and sooner the TCM software recall and valve body warranty extension will show up for the gas powered light trucks.

NHTSA Online Complaint Form

It was rough shifting on the way home from the dealer, particularly while just cruising and feathering the throttle at or around 25-35mph. Also, pulling away from stop signs or lights. The easier we were on the throttle, the worse the shutter was.

We've been told that installing 3rd party parts will void the warranty. I'd like them to fix it, just sooner rather than later is the gamble were playing with here.

 

[jfoj]

@jensenswanson

Thanks for the response.

A few questions, no SES/CEL/MIL light came on?

Have you ever driven a vehicle with the DFM? Wondering if part of what you were felling was DFM kicking in and out?

Did the dealer pull the vehicle apart? If not, I would pick it up, and drive it with the Auto Stop/Start turned off and then operate the transmission ONLY in L9 and see what happens. At least you might have transportation for the time being.

As for voiding the warranty on the valve body, funny thing it is you were to have someone other than GM install the valve body kit, it would very difficult for a GM tech to even notice a difference in the valve body. GM techs would rarely disassemble the valve body, they would perform a direct exchange. Seems that the valve body problems are VERY prevalent and it is part of the design. Not sure what the newer valve bodies will have different that may help these problems. The metal seperator plate with the paper gasket appears to be a major internal leak point for the valve body, probably due to the difference in expansion and contraction between the aluminum valve body and the steel seperator plate. I am pretty sure the NextGen kit eleminates the paper gasket and has a thicker seperator plate. I know on one of the RAM truck kits they have a much thicker aluminum seperator or spacer they offer for that application.

Valve body problems are nothing new since most transmissions have switched to aluminum over cast iron for the valve body. Valve body wear due to valve gouging has been a big issue alone with internal leaks around the seperator plates.

Good luck and let us know what happens, seems MANY people have been parked for 4-5+ weeks at this point, hopefully parts will be moving out soon.

 

[jfoj]

@Blanch44

How long ago were you waiting on a valve body for 2 months? Recently?

What were the symptoms that caused you to take your vehicle to the dealer? Lights? Harsh shifting? Codes?

 

[jensenswanson]

@jensenswanson

Thanks for the response.

A few questions, no SES/CEL/MIL light came on?

Have you ever driven a vehicle with the DFM? Wondering if part of what you were felling was DFM kicking in and out?

Did the dealer pull the vehicle apart? If not, I would pick it up, and drive it with the Auto Stop/Start turned off and then operate the transmission ONLY in L9 and see what happens. At least you might have transportation for the time being.

As for voiding the warranty on the valve body, funny thing it is you were to have someone other than GM install the valve body kit, it would very difficult for a GM tech to even notice a difference in the valve body. GM techs would rarely disassemble the valve body, they would perform a direct exchange. Seems that the valve body problems are VERY prevalent and it is part of the design. Not sure what the newer valve bodies will have different that may help these problems. The metal seperator plate with the paper gasket appears to be a major internal leak point for the valve body, probably due to the difference in expansion and contraction between the aluminum valve body and the steel seperator plate. I am pretty sure the NextGen kit eleminates the paper gasket and has a thicker seperator plate. I know on one of the RAM truck kits they have a much thicker aluminum seperator or spacer they offer for that application.

Valve body problems are nothing new since most transmissions have switched to aluminum over cast iron for the valve body. Valve body wear due to valve gouging has been a big issue alone with internal leaks around the seperator plates.

Good luck and let us know what happens, seems MANY people have been parked for 4-5+ weeks at this point, hopefully parts will be moving out soon.

No mil or other warning lights ever came on. Just felt the shuttering... The dealer here has given us a '24 Yukon XL with the 6.2 loaner and it drives much nicer and smoother than I ever had with our new one.

At this point I'm looking for GM to make things right, as they should have for a $100k+ truck. Also, I don't want to pay more out of pocket to fix their problem. If our warranty was nearly up I might risk voiding it but at this point I have a long way to go and feel that's worth it with this problem potentially/likely persisting.

I also hope/pray parts will be available soon!!!

 

[Doubeleive]

It was rough shifting on the way home from the dealer, particularly while just cruising and feathering the throttle at or around 25-35mph. Also, pulling away from stop signs or lights. The easier we were on the throttle, the worse the shutter was.

We've been told that installing 3rd party parts will void the warranty. I'd like them to fix it, just sooner rather than later is the gamble were playing with here.

it is rare that gm actually replaces a transmission part, usually if say there was any kind metal found in there they would just slap a reman in it with a 3yr 100k warranty and send you on the way. that being said if you had 3rd party parts installed it's unlikely they would ever even know about it unless you opened your mouth and inserted foot.
being that it is currently a known specific issue with the valve body it is the only reason they are opening it up and replacing anything.
It would be a freak accident if they actually tore down a transmission and found any 3rd party part in there, there too lazy for that in almost all cases
the only thing they might actually rebuild at the dealer is differentials, if it was a seal leaking or something basic that they can do quick and easy.
normally they will just r&r stuff unless you are paying out of pocket and request a rebuild of "whatever" even then it's limited to certain things and it may even get farmed out to a 3rd party shop, like head resurfacing, etc

 

[jerry455]

I just had a new trans installed at my Chevrolet dealer. I bought a used, 70,000 miles, 2021 Suburban High Country 4WD last May. Last November my truck started to shift funny. I installed a new trans filter and fluid in the truck over Christmas. I didn't really help. Fluid was a little dark but not burnt. End of January it started to hesitate and search for gear. It was debating about a trans repair shop or Chevy dealer where I bought it. They inspected fluid and said it was burned and had metal in it. They put a new trans in it for $5,017. It works perfect now. They had it a month and after a week they asked if I wanted a courtesy car. They gave me a brand new 2025 Blazer. Not the same as my Suburban but I was impressed that they were trying to help. It did not have any light on just erratic and slipping shifts. I don't know the history of my truck before I owned it. I have replaced every other fluid and will continue to replace fluids religously. I love the truck and hope to drive it forever. I put almost 10,000 miles on the truck from purchase to trans replacement. It drives fantastic and pulls my travel trailer extremely well. I originally thought to take it to the dealer after seeing all of the bulletins about the 10 speed trans.