r/gmcsierra • u/Jermi321 • Apr 10 '25
🔧Performance Upgrades 🔧 Next Gen Drivetrain Project Carbon Valve Body Upgrade
https://nextgendiesel.com/collections/10l80e-valve-bodies/products/project-carbon%C2%AE-10l80-e-diy-valve-body-upgrade-kit-v3-1?variant=44018016157869Has anyone proactively installed the Next Gen Drivetrain valve body upgrade kit? GM's software update does nothing to address the root cause of the 4th clutch auto engagement issue. It is a valve body mechanical wear issue causing fluid to bypass the valve causing an inadvertent 4th clutch to engage simultaneously with the other 3 clutches causing the transmission output shaft to lock up. The Next Gen kit is advertised as a mechanical solution to the shift valve wear issue.
I have noticed on several trucks that the fluid is damn near black at 45,000ish miles. My impression is if the valve body wear is gradual, then maybe over time the fluid leaking by the shift valve is not enough in the beginning stages of wear to cause the clutch drum to fully engage, but rather enough is leaking by to cause the clutch drum to partially engage causing a clutch slippage issue which is causing the fluid to look burnt in such a short time frame. I am looking to proactively take care of the issue GM will not. Truck has 3800 miles on it and I cannot afford to be without it for months at end.
TLDR: Thoughts on installing the valve body upgrade as a failure prevention upgrade.
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u/BulkyMarch9981 Apr 10 '25
Had my valve body go out at 18k and had it replaced. Not sure what transmission I have, but it was on a 2023 Denali 1500 3.0
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u/Jermi321 Apr 10 '25
Should be the 10 speed as well. The issue you had with your valve body is what I am researching how to prevent with the above-mentioned kit. It is a shame in today's age most new vehicle purchases require choosing the vehicle/brand issues we are "comfortable" with instead of pure quality and reliability. I am not hating, just stating the reality of today's new vehicle market.
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u/BulkyMarch9981 Apr 10 '25
If you got the money to replace it now, I would. The coolant control valve went out at 30K and my truck spent 2 months in the shop.
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u/Jermi321 Apr 10 '25
Your experience is what has me choosing to be proactive instead of relying on momma GM. I hate to hear your experience went so poorly! I am seriously leaning towards installing it. I am going to install a drain plug in the pan to help with future services as well.
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u/DORTx2 Apr 11 '25
Mines in the shop for a failed valve body right now and I'm looking into these options as well. Really don't want to void the warranty, on the other hand I don't want my truck stuck for 2 months 1,000km from home.
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u/Jermi321 Apr 11 '25
I hate to hear your truck is in the shop. I am surely hopeful for your truck to get back home with you soon where it belongs. Has the dealer given you a guesstimate as to when the repair will be complete?
I also have concerns about warranty issues, but to be honest, I am of the mindset to just fix the problem myself. It is one of those 'Lesser of two evils' type situation.
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u/DORTx2 Apr 11 '25
Nah the dealer said the part is in the rare category of "no ETA" which is pretty much worst case scenario. They said the few times they've had a part say that it's a multiple week wait minimum.
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u/Jermi321 Apr 11 '25
Dang! That freakin sucks! Hopefully that "no ETA" status changes really soon. I would be in a bind without this truck.
I am going to order the valve body kit and just send it. If nothing else, after I upgrade the valve body, the valve body will not need replacing when GM voids my transmission warranty for fixing their design flaw.
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u/DORTx2 Apr 11 '25
Well let me know how it goes, id say it's a good idea to get the upgrade, it's too late for me unfortunately. I use my truck for work and they gave me a Nissan rogue as a loaner and it's just not up to the task, so it's frustrating.
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u/Jermi321 Apr 11 '25
I plan on documenting the install and tips on how the upgrade and drain and fill procedure goes from a DIY standpoint along with a complete actual price breakdown. My estimate so far is $1034.00 for parts and supplies.
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u/Choice_Leader_8213 Apr 13 '25 edited Apr 13 '25
I have a 2024 Yukon with 6000 miles. Spoke to the Next Gen Project Carbon Design Engineer in length the other day. I have automatic transmission rebuilding and repair experience, did most of my own transmissions, did a few side jobs here and there as well.
I decided after speaking with the Next Gen guy that this would be worth proactively doing like you are planning. Next Gen offered to sell their solution or the rights to GM and GM pretty much blew them off and expected them to just give their solution to GM.
I figured it is pretty much a "When" not "If" situation. I went ahead and spend the extra money on the 6 shift valves as well. Figured I would go ahead and do the entire job.
Not worried about any warranty issues, GM will never know you did anything to the valve body. The dealers are pulling the assemblies and installing reman units. The problem is the Reman units are no where to be found at the moment. I have heard people waiting 3 months and still no ETA, have hear 2025 having problems in less than 1000 miles. If I had a problem now, I would pull the vehicle out of the dealer, order a Next Gen Project Carbon kit and either do the job myself or have a local trans shop do the work. Being without a vehicle for months and months is not worth the $2k you would likely spend to get the job done in a week!
I expect that the 2023-2025 models will ALL be recalled as well for the valve body problems. I doubt the early 2025 units had the updated TCM software installed. The software does not solve the problem, it is just a bandaid so GM did not need to replace all the valve bodies!!
As you mentioned, the problems with these valve bodies will cause premature transmission wear and tear and this is NOT covered under the extended Valve Body warranty for 15 years/150,000 miles. So while the cause of your transmission failure may have an extended warranty, your broken transmission is your problem after the Powertrain warranty has expired.
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u/Jermi321 Apr 14 '25 edited Apr 14 '25
Thank you for your detailed and informative response. Sounds like you and I are of a similar mindset about GM's resolution and how to go about curing the issue.
What is your take on adding the shift valves in addition to the kit? During your conversation with Next Gen, did they explain to what their experience with shift valve bore wear? I would be more inclined to add the shift valve spools if I had a more detailed and informative explanation for the need. Is the need purely because of bore wear, or did the Next Gen engineers actually change the geometry of the valve spools. .
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u/Choice_Leader_8213 Apr 14 '25 edited Apr 15 '25
What the Next Gen guy conveyed is in the years of rebuilding transmissions they took what worked and did not have problems from other manufacturers was considered. They also wanted to try to offer a solution for under $1k for a solution. So they balanced the option of the making the kit with the shift valves but that ran the cost up because the valves are not cheap to produce. After discussions and my plan to hopefully keep the Yukon for some period of time, plus I would be pulling the valve body anyway, I would spend the additional money for the valves because they pretty well convinced me that the shift valves would be the best option to reduce/eliminate valve body bore wear. To my understanding there was not any specific change in the valve design.
A few notes, I questioned Next Gen about fluid fill and bringing the trans temp up to the 200+ range and was told this is really not necessary, easier to fill cold, start engine, make sure fulid it topped off, allow engine to run and fluid to warm up to around 100-120F with plug out and allow any fluid expansion to drip out, then install plug, typically while engine is running. Then maybe check a few days later to make sure level is still good. Trying to check fluid with temps over 200F is dangerous.
The other thing is some of the bolts are torque to yeild, one use bolts. I think for the filter and there are also some bolts that have a special sealer on them that if not replaced may cause internal fluid leakage and low pressure to some of the clutch packs. Still looking for more info on this but have ordered this bolt kit GM Part #24050764 which superceded GM Part #24294356.
https://www.youtube.com/watch?v=XwDzWnwAiuk
https://www.youtube.com/watch?v=d0Tm5OlOYuE
I have also being doing many things to counter the 6.2l failure to include DFM and Auto Stop/Start bypass, running 5W30 or 0W40 engine oil, running 9 quarts with filter change, 8 quarts is about 2/3 quart low on these engines, installing a magnetic oil drain plug, changing the oil when the OLM hits 50%, adding a Catch Can and not allowing the engine to warm up at idle.
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u/Jermi321 Apr 14 '25
Makes perfect sense thinking of it that way. If the other valves are wearing out bores, then stands to reason the shift valves would also wear their respective bores.
I have added the Range module to my truck already and am quite happy with it. I understand it doesn't fix the lifter problem, but now it runs like it is supposed to. It also deleted the Auto Stop/Start as well. I have been looking into the RXP catch cans and am going to be installing one on the truck as well.
I changed the factory fill oil at 693 miles and just changed the oil again at 3,628. I will send the truck in for it's "free" service at 7,000. Then, change the oil, trans fluid and filter, differentials fluid, and transfer case fluid at 10,000. This is when I will be pulling the valve body and adding the Next Gen components. After that, my plan was to change the oil at 5,000 mile intervals and do oil analysis to confirm that interval. I also have the 6.2L
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u/bschwoerer184 Jul 17 '25
i just finally got gm to approve the install of the next gen valve body kit...although i have to pay for parts...i just want my truck back as its been 4mo and all they gave me was a buick envision to drive...i had 32k on before i had a trans code...if they install do i ask for pics/docs of trans if there's evidence of further damage? don't want to spend $1.5k on parts for a damaged trans. i talked to a few local shops and they said they seen this cause damage to warranty new transmission the dealership said same thing but with a much lower likelihood, in that case don't they just install trans with same shitty valve body? same with dealership putty in oem parts? same shitty valve body? i'm willing to pay to get my truck which has been amazing(1500 denali 3.0 w/6.5 bed and all options)
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u/Choice_Leader_8213 Jul 21 '25
Smart move moving on and going with the Next Gen kit. Did you get the shift valves as well? This runs the cost up but is worth it IMHO. I think lately they only sell with the shift valve now? No since waiting on the dealer for the same crappy rebuilt valve body. Spend your money and move on. Small price to pay for reliability.
If the dealer does a good job with the install and there are no other problems with the transmission you will be very happy with the end result. I question the dealers actually filling the transmission correctly, the engine needs be running when the final fluid level is set. For the most part they do not need to brake torque/power brake the transmission to get the fluid up to 175F, this is stupid and dangerous. Someone can get badly burned.
I finally got around to my install about 3 weeks ago and the transmission clearly shifts more precisely, with less overlap and gear change flare and has a slight firmness to the shifts which I like as butter smooth shifting usually means excessive wear.
Best to have the fluid checked again about 100 Miles after the transmission repair is performed. Either DIY on ramps or find a decent shop to do it. Again, the level NEEDS TO BE SET WITH THE ENGINE RUNNING. Fill until fluid just starts to drain out fill port.
The good news about the 3.0l Diesel is you do not need to drop the front of the exhaust like you do with the V8 engines in the 1500 series, I think the 2500+ vehicles may have more room with the 10L1000 and more space for the exhaust Y pipe.
Suggest you change the fluid every 20k miles, because dropping a stock pan will only have about 4-5 quarts of fluid.
Here is the thread about my install with pictures, tool list and other details.
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u/speenteen Jul 14 '25
Purchased my first diesel a few months ago and I have the 3.0L Duramax with the 10L80 transmission. Wondering if this would be a good idea to do as I have about 2300 miles on the truck so far. However, the one caveat is that my truck came with a lifetime power train warranty. With that being said what are y’all’s thoughts? Thanks for the help.
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u/bschwoerer184 Jul 22 '25
thanks man! just wanted to double check something...you replaced the oem check balls with torlon balls...did next gen not have these in kit? if im having someone do this id want these installed also.
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u/Choice_Leader_8213 Aug 02 '25
No, the NextGen kit did not have the Torlon check balls, you will need 10 and I would suggest you get the Sonax Torlon check ball kit.
Also suggest you get the GM bolt kit as well.
Suggest you read this for more details
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u/bschwoerer184 Aug 02 '25
thanks man for all the info, advice, and for answering my questions...all parts are ordered and the dealership is going to be installing.
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u/Choice_Leader_8213 Aug 04 '25
Good luck with everything, hopefully the dealer will do a good job with the update, it is really not too difficult. If done right you will find the shifting is so much better, especially the 2-3, 3-4 shifts.
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u/bschwoerer184 Aug 04 '25
well i ordered all the parts, went on a camping trip, and got a call from dealership this morning saying the warranty valve body was installed. apparently my service rep and his manager whom i was working with were both on vacation and didn't let anyone else know the plan...so not sure what i'm gonna do...they're offering me extended warranty so i guess ill upgrade when it takes a shit again
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u/Choice_Leader_8213 Aug 04 '25
Dealers are FAMOUS for lack of communication. Since you already purchased the parts, I would probably get an independent shop to install even in the replacement valve body as they are no different than what came out of the truck.
I installed the NextGen kit in my truck at about 8500 miles, just because I knew it was more WHEN than IF.
If you do plan on getting the kit installed if you have a V8 truck, get an aftermarket trans pan with the drain so you can at least drain the fluid every 2nd or 3rd oil change easily.
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u/bschwoerer184 26d ago
update! had truck 8 days maybe...went in limp mode and threw transmission service warning
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u/DeviceGloomy5610 17d ago
Unbelievable. I’ve just suffered from this issue today. Limp mode in 5th going up a big mountain. Acted funny yesterday, but reset today. Check engine light even went out, which I’ve never seen before. Sadly, a work friend with same truck got a Lemon Law company involved and GMC is buying his truck back.Â
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u/Logical-Geologist384 Jul 25 '25
I bought the kit for my 21 6.6 W 10 speed , the reviews i have found are not good and im hesitant to install it as my trans is fine but also wanted to do it proactively . I have not been able to find any positive experience with this company
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u/seksismart 10d ago
1 post history.
The account is bashing next gen, which is SUPER REPUTABLE and has a lot of amazing videos on utube about the topic.
Yeah... This so definitely is not a paid disinformation account...
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u/bschwoerer184 17d ago
apparently in some states there's a cash and keep option for lemon law...where you get cash for inconvenience of repairs and get to keep vehicle...anyone else here about this
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u/Clear_Blacksmith3712 17d ago
We installed their kit in several trucks in our fleet because couldn’t wait for valve bodies. All went perfectly. We did have some questions on the first one but they have a hotline and were always easy to work with. If we ever needed to leave a message we heard back pretty quickly, same day every time. All of the vehicles run at around 140 degrees and shift perfectly.
The valves are SUPER HEAVY. It’s shocking how much heavier they are than factory, it’s clearly over built stuff. I don’t pay for these vehicles we installed them in but if I had one of my own I would install the kit, zero questions asked. The peace of mind is worth the price, not to mention how much better they run now. All were 6.6 L5p except one that’s a gas truck. Hope this helps.
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u/shawizkid Apr 10 '25
No but also interested.