Project Carbon Next Gen 10 Speed Valve Body Kit

Just putting this initial info out about the Project Carbon Next Gen 10 Speed Valve body kit for anyone that wants to follow along.

I contacted Next Gen and spoke at length with the design Engineer that came up with the Project Carbon valve body repair/update. Spoke about many topics but it seems they have done their homework on this update and found many things about the OE valve body design and parts choices that are causing problems. They drew from experience from all the other transmissions they have repaired over the years and took what worked and lasted from other manufacturers and applied the materials and techniques to the GM OE valve body.

Mostly it comes down to higher quality machined steel spool valves that are properly chamfered and highly polished, one piece thicker laser cut valve body separator plates without the need for paper gaskets that can fail and getting rid of the steel, not even stainless steel, filter screens that tend to tear and end up with steel wires from the screens getting caught up in the magnetic control solenoids and/or jamming spool valves in the valve body. They also have some modifications for the lube circuits as well as some other precision machined steel valves with O-rings that will not wear the valve body bores like the standard poorly machines aluminum valves in the OE valve body.

I put the Next Gen representative on the spot a bit about how many of these valve body kits they have sold and he is more on the Technical side and not the Sales side, but he said in the range of 4000-5000 kits.

I decided to Preventatively and Proactively purchase the full Project Carbon valve body upgrade kit with the addition of the billet shift valves, which are not cheap, and the total with shipping came out to around $1500.

Some people may say why am I doing this. Part of the reason is I have built automatic transmissions in the past, modified valve bodies and dealt with similar valve body problems so I understand what this kit changes, upgrades or modifies. I also understand how the valve body bores can wear over time with aluminum valves riding in aluminum valve body bores. The other issue is what happens when the valve body starts to have internal leaks and/or valve body bore wear, the application of the clutch packs is impacted and the clutch packs can start slipping and cause more advanced wear in the transmission. Some may not be able to detect some of the slippage, but you will clearly feel harsh or banging during shifting. Since these transmissions are pretty smooth shifting even of you are the daily driver and are trying to be aware of any change in shift slippage, you may not notice problems until additional clutch pack wear has occurred.

My goal is to head off any serious transmission clutch wear. While the 2023+ light trucks have not been recalled, I expect they will based on a lot of searching I have done online and the failures I am even seeing even with some of the 2025 models. I would have assumed GM may have updated the transmission software on the 2025 models, but maybe they did not get it in the earlier builds. The Recall is only for a software update that DOES NOT CORRECT OR FIX the valve body problems. All the Recall does is update the transmission control module software to "detect" wear and slippage and to put the transmission in a "Limp" mode that will not allow the transmission to shift above 5th gear, limiting the vehicle to about 45 MPH. As part of the "Recall" if your VIN is covered, GM will extend the valve body and only the valve body warranty to 15 Years/150,000 miles. The rest of the transmission does not have the warranty extended and a faulty valve body can cause excessive wear or possible failure within the transmission. I think it is still too early to tell if the transmission software update can really "protect" the transmission from lower pressures applying clutch packs and premature transmission clutch pack wear.

I plan on personally pulling the valve body and installing the Project Carbon valve body update kit hopefully before my truck has 7500 miles on it. I will update this thread with pictures of the kit parts once received and try to get some pictures during the valve body upgrade and determine how difficult a job this will be. It is a bit more work and advanced than changing the transmission fluid, but I would hope that someone that could do brake work or replace a water pump could do this work. Next Gen says most people can do the job in about 3 hours in the driveway. You could also have a local transmission show install the parts probably for about 3 hours of labor and fluid locally if you do not think you could do the work yourself.

I do a lot of long haul trips and I would rather head off problems, even if I have to pay for it out of my own pocket. At the moment I am seeing too many stories of owners that have been held up for 2-4 months waiting on a GM rebuilt valve body that may not be much better than the the original the vehicle shipped with. I assume at some point the months long delays may get much shorter, but a valve body problem will at a minimum probably cause at least 3 days loss of the vehicle in most cases. Again, based on the searching I have been doing, I am seeing 2023-2025 models with these valve body problems, some with as few as 1,000 miles! I personally think this is a more "When" than "If" scenario. I do believe that the 2022-2025 models will likely be recalled based on the recent Cadillac and Camero recall.

I would rather take my chances spending my own money and time on what appears to be a superior set of parts to address the problem before it becomes a "problem".

Again, some may way why do this, you have a warranty, I say I do not want the hassle and potential for additional transmission clutch pack damage. I would rather have control over the repair in my driveway than at the dealer, this is just me. I have the skills, experience and tools to do this job, so it will get done depending on my schedule.

I have already done a lot of things to try and keep the 6.2l alive: DFM and Auto/Stop Start bypassed, Catch Can installed, Magnetic oil drain plug, no remote starting or allowing the truck to idle to warm up especially in the Winter, 3rd oil change before 6,000 miles, no 0W20 crap in the crankcase, running 9 quarts with oil filter.

So we shall see how things go, will try to add updates as I get parts and have time to perform the valve body upgrade.

Project Carbon Valve Body

Project Carbon Repair Story

As the world burns!

Fantastic info thanks.

It is good to know an aftermarket upgrade exists.

This is like the east coast bushing upgrade for Toyota needle bearing failures: the aftermarket had a really good solution that was cost effective.

There are a few other way cheaper options/kits from Sonnax, Suncoast and other transmission related vendors, but you need to be very careful, a lot of these kits are mostly springs and maybe a few seals or O-rings, some do have some spool valve sleeves, but on some kits you actually are required to cut the spool valve stems with a grinder to a specific length.

Few kits really address the OE factory sepraator plate problems, address partial bore wear and have precsion machined, highly polished replacement spool valves that should last far longer without damaging the valve body bores that the OE aluminum spool valves. Sure you could replace the factory metal separator plates with an OE replacement, but these have been known to be constantly failure prone.

I expect minimal updates to the replacement GM valve bodies they will put in vehicles during the 15 year/150,000 mile extended warranty period. Once they have primed the supply chain with valve bodies, the remaining will all be remanufactured either by GM or a contractor.

A couple quick updates while I am waiting on the shipment of the valve body kit.

Went ahead and purchased the GM Part #24050764 for around $15 which superseded GM Part #24294356. These are 1 time use bolts with some special sealer on a few that should keep internal leakage from occurring around the threads of a few specific bolts. I think they may be for the filter and a few for the valve body, but I will do more research and make sure other bolts are not required as sometimes there are Torque to Yield one use bolts for things like valve bodies.

Since the OE pan has no drain which is typical, some earlier versions have a small plug on the bottom of the pan, but this not technically a drain, it is for filling, you can pull the plug and it will drain some fluid, but not much and it takes a long time as it is only about 5/16" diameter.

I decided to get an aftermarket transmission pan mainly because it has a drain plug integrated into it. Decided to go with the PPE pan, it holds 2 additional quarts, not a bad thing, but I really wanted a drain plug for ease of partial fluid changes. I figured if I could pull a drain plug and at least change a good portion of the transmission fluid as easy as changing oil, I would be more inclined to drain and refill every 10k miles and then about every 30k miles drop the pan, clean it out change the filter and refill. The filters on these transmissions are typically more of a fine metal or plastic screen from what I have seen, so they may not really need to be changed often. Once I get my valve body out, I will try and post a picture of the OE filter type with a description.

While some may think I am foolish for doing this while I do not seem to have a problem and the vehicle is under warranty, my take is I would rather head off the problem now, save the transmission and possible more costs later in the ownership cycle. I mean there are plenty of members here and other owners that immediately put larger wheels and tires on the truck or modify the intake or exhaust within months of purchasing the vehicle. This is typically far more money than I am spending on my transmission at this point. I am just putting money into what I deem as reliability rather than other things.

Everyone has their wants and needs, I want to try and control possible future failures and hopefully put off premature damage occurring to the transmission as well as letting me control downtime for maintenance and repairs. I fully understand there are other failure points within these 10 speed transmissions, however, I feel a number of the premature failures can be directly attributed to failing valve bodies. Some problems like the pump gear whine may just happen no matter what, but hopefully fluid services and lake of heavy towing and loads will keep this specific problem from occurring. I may not have all the bases covered, but the valve body is a pretty failure prone part from the research I have done and I think I am investing my time and money in the best place at this point in time. Prefer to have this happen on my schedule and not someone else's timeframe.

My PPE aluminum trans pan with drain arrived yesterday, I have not unboxed it yet, but that dude is freaking HEAVY!! It must be a pretty solid casting. If comes with bolts for the trans pan as I assume they may be a bit longer than OE due to the aluminum pan flange thickness. For my 2024 Yukon 6.2l the PPE part number is listed as #128051300. Please double check your application on the PPE website before ordering because some of the descriptions are somewhat vague or confusing as I think there may have been changes mid run for application on the GM trucks. Will compare and update once I get into the job.

I have the trans pan gasket, fluid should be here tomorrow. Ordered a decent container/pump, kind of like a garden sprayer, I could have used one and modified it, but this trans fluid container pump was not too expensive, if it make life easy, I will change the fluid more often!

Waiting on the GM bolt kit and the NextGen valve body still. I think bolt kit will be here Friday. Not sure the valve body kit has shipped yet. I ordered the 6 shift valves with the kit, more $$$$ but figured I might as well do the entire job while I am at it. Possibly the delay is the shift valves? Hopefully I will get a notice of shipment in the next 3-6 days.

As far as I know, I have not noticed any transmission related problems, but I want to get this weak point knocked out and off the table as a future problem. I drive too many longer trips and I have no interest in finding out when the valve body will act up.

Seems the transmission problems are now more frequent than the 6.2l bearing failures at the moment. I guess we are all in the same boat with the valve lifter problem, these have not been on the radar lately due to all the 6.2l bearing failures.

Today's update for anyone that is silently following along in the background.

GM valve body bolt kit arrived
GM ULV trans fluid arrived
Fluid pump arrived

Ordered a 10L80 manual just to have it as I plan on figuring out how the thing actually works! It was only $45 so I figured what the heck, I may actually learn something and if I find I no longer need it, there is always ebay!

Ordered a smaller Sonnax 10L80 Zip kit because there were a few small things in this kit that I do not think the NextGen kit offered. Maybe NextGen did not see a need for the few items the Sonnax Zip kit supplied. I will inspect the valve body and probably make an audible on whether I may use any of the parts from the Sonnax kit. The Sonnax kit came up WAY short and WAY cheaper than the NextGen kit, but they did not have the valve body separator plates and only a few valves and sleeves. Again, I will make a judgement call on the Sonnax parts once I am into the valve body.

Waiting on NextGen valve body kit and the Sonnax Zip kit. Once these get here, then I have to look at my schedule when I can tear into the transmission.

Great post from Camero forum with pictures installing the Project Carbon Valve Body kit in a Camero 10L60 transmission which should have the same valve body as the 10L80 transmission we have. There may be a slight difference in the electronic shift and electronic/hydraulic Park.

I mean as a former gm transmission tech I think you are going a bit overboard. But it's your vehicle and money so long as it makes you happy.

How are you running 9 quarts tho? You have a larger oil pan?

Problem with replacing parts that are seemingly find so early is that when vehicles fail it's usually early. And you replacing that component and if you end up having problems you have just muddled up the water further.

2nd I've done thousands of transmissions and I am not going to replace my valve body in my drive way lol.

No way. I want a lift and to have access not to mention the fluid everywhere as it slowly drips everywhere even tho it's been drained.

I'm also curious to the thousands they claim they have sold. Seems suspect.

Hope it all works out.

You and other may think I an going overboard, but this is what the world has come to, premature engine and transmission failures. Designed down to a price, not to a level of reliability. This along with all the Federal Government EPA and CAFE requirements have tanked once reliable vehicles and turned them into fragile devices that need careful operation and maintenance. We have gone back to 1960's maintenance requirements. Based on everything I have researched, it is not IF but when. Similar problems on the 6 and 8 speeds as well with valve body wear and separator plate sealing problems.

The issue is with these internal leaks, clutch packs can have reduced application pressure and slippage. What happens is these leaks start out minor and you may not notice the problem until it gets really bad. By that time, you have started to cause excessive wear to the transmission and it may be a bit late for a simple valve body replacement. Understand on the units GM recalled, ONLY the valve body is warranted for 15 years/150,000 miles, not the entire transmission.

So I have the tools, skills and experience to perform the job, so rather than wait for the problem to happen, I will head off the issue and address it now.

Doing valve body work in the driveway is not a problem, I have done this before a number of times. Really not so difficult, sure a lift is better, but I have not spend $4500 on a lift yet!

Not so worried about fluid dripping, it will only drip so long. Not a problem is you have a decent drain pan!! Some folks miss the big picture on drain pans!!

Best $8 drain pan for large oil sumps and transmission work!

As for the 9 quarts of oil in the engine, the vehicle has a stock oil pan, but GM's spec of 8 quarts with oil filter for the V8's is not how they come filled from the factory!! Anyone running 8 quarts with a filter is asking for trouble. All I did was match what the engine was shipped with from the factory. Have crossed checked almost a dozen Yukons, Suburbans, Tahoes and they are would be about 2/3 rds low on oil if 8 quarts is used during an oil change.

Figuring out the stupid GM transmission fluid will will be fun as well. SO MUCH DOCUMENTION is conflicting and I believe WRONG. For the STUPID GM Engineer that came up with a fluid fill at around 180-212F is asking for problems and for people to get hurt. The smart fill procedures I have seen for other vendors was for the trans fluid to be at 100F, this is below burning temperature.

So many users are failing to use the fluid fill standpipe in the bottom of some of the trans pans. The fluid fill standpipe is a genius way to go, VW and other German manufacturers even allowed the standpipe to be unthreaded so you could actually drain most of the fluid via the standpipe hole. You can even fill easily via the standpipe hole as well, it is very easy, the convoluted and expensive tools they suggest are crazy, you can use a $8 fluid transfer pump from the parts store.

I will first be checking the fluid cold from the upper case fill port and taking a measurement. I will pretty much then measure the fluid I drain from the transmission and this will be my baseline. GM fills these transmissions "cold" or at least at a fixed temperature during assembly and I can guarantee it is not likely over 100F.

A quick glance under my vehicle I did not see the standpipe in the pan, but I need to check closer as it may be in a corner that I missed. But what I can say for sure there are plenty of DIY videos and posts on forums that I believe are way wrong and I have even seen a GM bulletin that want the transmission temperature up to close to 200F which is hot going to happen on my watch. I have yet to see the operating temperature of my transmission go above 160F so far.

So today's update.

Sonnax Zip Kit and Torlon Check Balls arrived. Decided to swap out the cheap nylon check balls wit hthe Torlon Check Balls. These are overall more durable than the cheap nylon OE check balls that may start to wear over time.

Project Carbon Valve Body Kit should be shipping today. They were waiting on a spool valve delivery.