Project Carbon® A466ND DIY Valve Body Upgrade Kit - V5.0

Next Gen Drivetrain, Inc.


     Welcome to the fifth version of our best-selling A466ND Project Carbon® DIY Valve Body Upgrade Kit. Scared of your A466ND’s skiddish reputation? Seeking to add power, or dissatisfied with the sloppy and flare-filled shifts? The A466ND is riddled with highly expensive problems that largely derive from a couple of leaky valves and a set of utterly useless accumulator pistons. This dinosaur of a transmission can be traced back to the Toyota Land Cruiser of the mid 80's and was never designed to accommodate the arduous demands of the Cummins diesel crowd.

     As always, Next Gen Drivetrain™ proprietary, machined in-house, best-selling drop-in Project Carbon® DIY Valve Body Upgrade Kits are the driving force in providing efficient and inclusive solutions to these evolving transmissions. This kit addresses both the leaky valves and the accumulation leaks, even going so far as to include drop-in sleeves to replenish the B1 and B2 valve bore and Secondary Pressure Regulator Valve Bore with NO machining needed! Further, it offers the only center support stud kit available. Best of all is our newly engineered Project Carbon® Dual O-Ringed Billet Steel Dampener/Accumulator set.

Aisin Seiki A466ND Product Resources:

- A466ND Transmissions
- A466ND Torque Converters
- A466ND Rebuild Kits
- A466ND Valve Bodies
- A466ND Parts

Popular Transmission Information Resources:

Top 5 Benefits of an Upgraded or Built Transmission
Calculating Torque Multiplication Factor, Why is it So Important?
Top 5 Ways to Extend the Life of a Factory Transmission

See Easy-To-Follow Instructions w/ Pictures Here:

>>> Project Carbon® A466ND Valve Body Upgrade Kit Install Guide & Tips


Difficulty Level: 4 out of 10

Install Time: 2 hours*

 *This kit comes with very easy to follow instructions and visuals to help you install the product as efficiently as possible. If you run into any questions or hang-ups, just call in and ask to speak to an expert!

Frequently Asked Questions:

Q: Does the Project Carbon®A466ND DIY Valve Body Upgrade Kit require a quick-learn or TCM Tuning to be done after install?

A: Absolutely not, just plug and play! You can use a TCM tune to increase line pressure, allowing you to get the most out of the kit, but it is not necessary to run the kit.

Q: Will this kit cause aggressive or banging shifts?

A: Nope! This kit will tighten shifts up slightly, but not to the point of being unsavory or aggressive. You will be pleased to notice quick, crisp, seemless shifts that you wish you would have gotten from the factory. We do this by closing the crossleaks found in even brand new OEM valve bodies, allowing clutches to turn on immediately when commanded.

Q: How does this product compare to other A466ND valve body upgrades on the market?

A: There is simply no comparison to other valve body upgrade kits on the market. Unlike other kits comprised of cheap, foreign-made parts that leave most problems unresolved, and worse, could have been pieced together yourself for less, this kit is 100% engineered AND manufactured in-house by Next Gen Drivetrain. Aside from seals and fasteners, all of these parts are designed by, and made by us. No expense was spared in the development of the best A466ND valve body upgrade kit on the market.

Q: I have low miles, should I wait until the vehicle has more mileage to run this kit?

A: No! This kit prevents the degradation and decay of countless internal parts that cause expensive failure. The best time to install this kit is when the vehicle is newer, before damage and decay has taken place.

Q: I have high miles, is it too late to benefit from this kit?

A: Also no! High mileage vehicles will benefit even more from this kit because they often have significant wear to internal components such as clutches and valves. This kit will restore and enhance hydraulic integrity to all of these functions, breathing new life into the transmission and adding to it's lifespan.

Q: I may rebuild my transmission in the future. Would that make this kit a waste?

A: Absolutely not! These parts are dramatically over-engineered and can be reused until the end of time. If you need to rebuild the transmission, you can reuse all of these parts. Even the seals generally do not need changed. If purchasing a Next Gen Drivetrain transmission, we can remove 100% of the cost of the kit from the price of a transmission. This kit can only help you.

Q: How easy is this product to install?

A: This product is very easy to install. Anyone who can follow basic instructions and has access to a relatively clean workplace can install this product right at home. Best of all, ALL Next Gen Drivetrain valve body upgrade kits install WITHOUT dropping the transmission. These kits include detailed instructions, but if you get stuck, we will personally walk you through the installation by phone.

Q: Is there any downside to installing this kit in my vehicle?

A: None. This kit provides a huge reliability AND drivability improvement for the price of a basic tune-up. Best of all, if installed in a vehicle that is currently in good working order, our valve body upgrade kits can often prevent the need for a transmission rebuild in the future for the average person altogether.

You can expect:

- Much better shifting

- Tremendously increased longevity, resolving the dreaded B1/B2 leakage issue!

- Better clutch control

- Fixes crossleakage better than any other DIY kit on the market 

- Cooler Operating Temperature

- Fixes problematic Line Pressure Bleedoff issue at High Heat/Pressure

*For those who are not in the market for our complete and ready to install valve bodies, this is the perfect DIY solution that ANYONE can do, and is designed to address the major failure points of the A466ND once and for all.*

This kit consists of:

- 5 Billet Steel Project Carbon® Dampener Pistons

- 1 Billet Steel Project Carbon® K1 Accumulator Piston 

- 10 Small High-Temp Accumulator Piston O-Ring Updates

- 2 Large High-Temp Accumulator Piston O-Ring Updates

- 5 External Project Carbon® Recalibrated Dampener Springs

- 5 Internal Project Carbon® Recalibrated Dampener Springs

- 1 Project Carbon® Recalibrated Accumulator Piston Spring

- 2 Hardened Steel Zinc-Coated Center Support Studs

- 2 Steel Torque Washers

- 2 Hardened Steel Zinc-Coated Fasteners

- 1 Billet B1 Control Valve Sleeve

- 1 Billet B2 Control Valve Sleeve

- 1 Billet Secondary Pressure Regulator Valve Sleeve

- 1 Anodized B1 Control Valve Plunger

- 1 Anodized B2 Control Valve Plunger

- 1 Anodized Secondary Pressure Regulator Valve

Billet Steel Project Carbon® High Pressure Pistons:

     The Aisin Seiki A466ND manages oil pressure through accumulation in an extremely similar manner to it's predecessor, the AS68RC. This is nothing new, accumulation dates back to the 50's! Accumulation systems simply provide a "shock absorption" effect to oil on it's way to the clutch pack, enabling smoother shifts. As a result, it's one of the first places to look when seeking to improve the shift quality of a transmission. TheA466ND is notoriously a horrible shifting transmission with dismal self control, and for this problem in specific, our Project Carbon® Accumulator & Dampener Piston Set is absolutely imperative!

     To begin, we remove the factory pistons and springs entirely, they will become trash during the installation of our kit. The factory pistons are smooth-bore, featuring no O-Rings, PTFE Seals or otherwise to prevent billowing volumes of crossleakage. Additionally, the springs behind these pistons are insufficiently weak to ensure progressive and safe application of line pressure. These springs have been found broken but more frequently, do not hold the adequate pressure to prevent fully bottoming out during the gearshift; a prime cause of "banging" shift complaints in this transmission.

     Our accumulator set was engineered and is manufactured entirely in-house to directly assert this specific issue. They feature 2 high temperature O-Rings per piston, one on each end, to suffice 2 purposes. One purpose served is to prevent oil from exiting the accumulator bore, much like to avoid compression from exiting a cylinder during the compression stroke of a motor by using piston rings. The factory pistons in this "motor" (transmission) have no piston rings.. how smart?

     There beyond, the second ring is to provide axial support that prevents the steel piston from making physical contact with the bore at any point. This permanently and indefinitely resolves bore wear as the piston never actually touches the bore. The ring protrudes and cannot be compressed enough to make the piston to cause physical contact. Translation? Longevity, longevity, longevity!

Recalibrated Project Carbon®" Accumulator Spring Set:

     As mentioned in the previous section, the springs often crush completely inside the well depth of the piston, enabling the pistons to bottom out against their retainers causing a "banging" shift, or in some cases are even broken when this occurs. Our Project Carbon® accumulator springs across various transmissions have a reputation for being unbreakable due to their immense cross-section diameters and commanding seat-pressures. 

     How does this solve your problems as anA466ND owner? One of the biggest complaints we found in market data amongst the driving behavior of the A466ND was that consumers feel the shifts are unpredictable, erratic, too soft, too harsh and simply never "just right." As instrumental as our pistons are for resolving this miasma of maladaptive behavior, so are our accumulator springs.

     These drop-in springs slide into our pistons, push rod in tappet style, and stay arrow straight. They are designed to be in excess of nose pressure to any line pressure figure the A466ND can produce under any circumstances, rendering it mathematically impossible for you to bottom these pistons out against their retainer. Further, their staunch pressure figures and double-spring feature amongst the dampener pistons ensures progressive and controlled shifts that are never aggressive. Simply a firm and concise shift oriented towards daily driving, practicality and durability!

Sleeved B1 & B2 Control Valve Sleeve & Plunger Set:

From the factory, the valves that control oil flow to clutch packs B1 and B2 are made from a low quality aluminum casting. They have poor tolerance control and feature a coarse inner valve that suffers from vacuum pressure issues that we've detected in valve bodies as young as 30,000 miles. By contrast, some customers experience good luck with these components into higher mileage. We investigated this and discovered customers who made it to high mileage figures often reported frequent highway driving and oil services; making these valves less susceptible to failure. Consumers who frequent stop and go driving conditions will use these valves more, causing them to leak much faster. 
     We absolve this concern from discussion by sleeving these valve bores with CNC machined aluminum sleeves. Inside, a drop-in anodized plunger valve with smooth bores will be inserted to ensure excellent longevity and negating the potential for vacuum leaks over time. Further, the cleaning lands found on the factory control valve are frequent catalysts of valve seizure. The anodized plunger and sleeve used in this kit travel in a perfect axial fashion preventing any potential for seizure.

Secondary Pressure Regulator Valve Sleeve & Valve:

     Perhaps most prolific of the A466ND valve body problems is oil pressure exiting the pressure regulator valve bore. Think of this as the bow of a boat, when it leaks, the boat cannot float. In transmission terms, the clutch pack cannot engage. Similar to our solution for the B1 and B2 control valves, we include a CNC machined sleeve and plunger valve designed to restore life to day one, and keep it there. This also enables you to maintain 100% of your line pressure even at high pressure or temperature figures. 

     This is important because the first place crossleaks present is at the top of the pressure and temperature ranges of the transmission, similar to boost leaks in a turbo'd motor. This drop-in modification will keep pressure pristinely confident about all usable ranges of this transmissions hydraulic systems.

Hardened Steel Zinc-Coated Center Support Stud Kit:

     The A466ND Center Support, much like many motor head assemblies, is fastened to the casting by low quality bolts that are just barely good enough to do the job. They often stretch, crack, work loose and otherwise. Further, as this happens the center support will begin to wear out extensively. It accelerates transmission failure and challenges power attempting to reach the output shaft of the transmission.

     Also akin to motors, replacing them with hardened steel studs can yield immense increases in reliability. These studs can be torqued far greater than the OEM bolts, but also come with a zinc coating to protect them from future wear. These studs are easy to install while the valve body is out of the transmission, and will halt center support wear in it's tracks.


     If you’re looking for a DIY solution to your A466ND that does not require a transmission drop, tremendous shop labor costs or going broke, there’s is no better product than our A466ND Project Carbon® DIY Valve Body Upgrade Kit. This bestselling product is easy to install, affordable and delivers huge improvements to the A466ND at any mileage or rebuild. If you still have questions, we encourage to call in and speak to one of our experts!