Robahr24
NAXJA Forum User
- Location
- Cleveland, OH
I thought I seen a thread of tranny mods but its a pain searching for it again. Has anybody got any valve body mods since you can't put a shift kit in them? Is it worth it?
-
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AW4 Valve Body Mods
- Thread starter Robahr24
- Start date
GrimmJeeper
NAXJA Forum User
- Location
- Gardena, CA
i would like to know about this too.
they DO make a "shift improver valve" that gets rid of the 1 second delay when you go into reverse, but thats about it as far as the off the shelf mods go.
they DO make a "shift improver valve" that gets rid of the 1 second delay when you go into reverse, but thats about it as far as the off the shelf mods go.
What are you trying to improve? Shift points? This is already one of the best & most reliable tranny's ever used in a Jeep. So what need's to be upgraded?
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
I have seen the post he was talking about as well. Don't recall where though, and I am a bit skeptical about what it exactly does to the tranny. I know I replied to it where ever it was.
So what was it about? Changing the shift points? boosting line pressure? Keeping the converter unlocked?
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
IDK... it is a thread.. and it does have tranny mods that relate to the valve body.. so.. maybe? best if he answered that...
5-90
NAXJA Forum User
- Location
- Hammerspace
There's an outfit called Level Ten that does AW4/30-40/A340 mods (same box,) but I'm not sure what you want.
The AW4 is electronically shifted, so making it a "manumatic" is a matter of electronics rather than hydraulics. But, you can make it a full-manual control slushbox with a little work.
Shift points on the thing - stock - are already pretty good, so I don't see why you'd need changes there.
What are you trying to do? If you tell us more, we can help you come up with ideas.
The AW4 is electronically shifted, so making it a "manumatic" is a matter of electronics rather than hydraulics. But, you can make it a full-manual control slushbox with a little work.
Shift points on the thing - stock - are already pretty good, so I don't see why you'd need changes there.
What are you trying to do? If you tell us more, we can help you come up with ideas.
RANSOM
NAXJA Forum User
- Location
- south jersey
http://www.importperformancetrans.com/toyotaauto.shtml
They will modify your valve body for quicker shifts and more pressure on the clutches. Or you can have a performance trans built to handle 1000 hp.
Robahr24
NAXJA Forum User
- Location
- Cleveland, OH
I was looking for quicker shift points, but yeah I found that a little after I made this thread. The valve body mod costs $650. Wondered if anybody had it done ?
Quicker shifts? Any chance you running bigger tires without regearing?
alexrule1234
NAXJA Forum User
- Location
- Jacksonville, Fl
From what I understand by changing the stiffness in the springs in the valve body it will shift faster. I have not tried the mod that was linked from jf yet since I am broke and could not afford a new transmission if it blew up and I am dealing with other jeep issues atm but I do want to eventually try it.
Hi all,
I found this thread and wanted to post further info on valve body mods so here's an article that I wrote and a link to instructions for removal and installation of a AW4 valve body.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Toyota Modified Valve Body
As many Toyota and Jeep owners know, the AW4 / Toyota 340, A340, and A341E series of transmissions are generally very well made and demonstrate excellent durability in unmodified applications. The framework is present for an extremely strong transmission that is to be used in a high performance or extreme duty application.
The problem is that the original calibration is engineered for driver comfort rather than ultimate component strength. The soft, sliding shifts that are part of the original design are not appropriate for increased horsepower applications, towing, off road use, racing, etc.
These calibration inadequacies quickly manifest themselves as extremely poor shift quality, and more often than not, severe damage to the gearbox is soon to follow. One of the most common symptoms of this is the engine stuttering or hitting the rev limiter during a full throttle upshift. Without going into too much technical detail, the factory shortcomings can be addressed through modification and recalibration of the control valve assembly, a.k.a. the valve body.
The valve body is a component that is comprised of valves, solenoids, an orifice separator plate and an intricate series of passages- it is the most complex component in the most complex part of your vehicle- the automatic transmission. The function of the valve body is to act as the "brain" of the automatic transmission- it directs hydraulic pressure to the appropriate clutches and bands at the right time to initiate upshifts, down shifts, selection of reverse, converter clutch application, etc. As well as controlling shift timing and shift quality, it is also responsible for directing hydraulic pressure to the cooler and the lubrication circuit. As you can imagine, the transmission's operational characteristics can be drastically altered and also customized to the given application through modifications to this component.
Because there are no commercially available shift kits for these transmissions, we began working on valve body modifications that were appropriate for Supras, Jeeps with the AW4 transmission, Toyota Tundra, Tacoma and 4Runner, and also Lexus SUV's and rear drive passenger cars- especially those that needed to handle the additional power that accompanies the installation of a supercharger, turbo or nitrous oxide injection.
At the risk of oversimplification, there are a few things that are done in concert to create much more favorable operation of the gearbox. The first thing that needs to be done is to increase the hydraulic operating pressure of the transmission- this pressure is known as "line pressure". All hydraulic functions of the transmission are based on this pressure- what is especially of concern for these purposes is the clamping force which is applied to the clutches and bands to get them to hold against engine torque.
In simple terms, increased engine output is complemented by increased line pressure and increased "clamp" on the clutches- this can be likened to a performance clutch with a heavier pressure plate spring in a manual transmission equipped vehicle.The idea is to raise this pressure only slightly at light throttle but increase it by 30-40% at full throttle- where it is really needed. The effects of this are shifts that are not overly uncomfortable at lower throttle openings, while at heavier throttle, firm shifts with much shorter clutch application time and increased clamping force can be achieved. An additional benefit of this is increased flow through the transmission's cooler and lube system.
Secondly, hydraulic pressure is normally routed through an orifice in a metal "separator plate" that resides between the two halves of the valve body before it gets to its intended destination. By altering these orifices, we can increase the volume of hydraulic oil that is used to apply the various clutches and bands.
The final part of modification is the alteration of the accumulator circuits. These are hydraulic circuits that are parallel to the components that are used for shifting. Their function is to absorb or "accumulate" some of the hydraulic pressure that is intended to apply a clutch pack or band. By limiting the action of what is essentially a "shock absorber" for each shift, we are able to further reduce clutch lock up time and shift lag at wide open throttle.
The end result is that shift time is reduced by 30 to 80%, depending on the amount of acceptable shift feel and the intended application. The clamping force that is required to apply the clutches and bands is increased by 30 to 40% at full throttle. Flow through the cooler and lube circuit is increased and the converter clutch application time is also reduced.Transmission and valve body upgrades are not only for American made vehicles anymore. Increased performance and more efficient shifting is now available for vehicles of almost every manufacturer thanks to the few companies that are willing to do the research and development work required for this rapidly growing segment of the automotive aftermarket.
For more information, please follow this link:
Toyota High Performance Transmissions
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
About The Author
John Lombardo, a.k.a. Transdude, is co-owner of IPT Performance Transmissions and has been in the transmission and high performance industry for over 20 years. Visit his website- http://www.importperformancetrans.com for more drivetrain information articles.
**This free reprint article is available for use in ezines,
forums, websites and blogs on the condition that the article
is not altered and the resource box remains intact with all
hyperlinks activated.
AW4 Valve Body Installation Instructions
-John
I found this thread and wanted to post further info on valve body mods so here's an article that I wrote and a link to instructions for removal and installation of a AW4 valve body.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Toyota Modified Valve Body
As many Toyota and Jeep owners know, the AW4 / Toyota 340, A340, and A341E series of transmissions are generally very well made and demonstrate excellent durability in unmodified applications. The framework is present for an extremely strong transmission that is to be used in a high performance or extreme duty application.
The problem is that the original calibration is engineered for driver comfort rather than ultimate component strength. The soft, sliding shifts that are part of the original design are not appropriate for increased horsepower applications, towing, off road use, racing, etc.
These calibration inadequacies quickly manifest themselves as extremely poor shift quality, and more often than not, severe damage to the gearbox is soon to follow. One of the most common symptoms of this is the engine stuttering or hitting the rev limiter during a full throttle upshift. Without going into too much technical detail, the factory shortcomings can be addressed through modification and recalibration of the control valve assembly, a.k.a. the valve body.
The valve body is a component that is comprised of valves, solenoids, an orifice separator plate and an intricate series of passages- it is the most complex component in the most complex part of your vehicle- the automatic transmission. The function of the valve body is to act as the "brain" of the automatic transmission- it directs hydraulic pressure to the appropriate clutches and bands at the right time to initiate upshifts, down shifts, selection of reverse, converter clutch application, etc. As well as controlling shift timing and shift quality, it is also responsible for directing hydraulic pressure to the cooler and the lubrication circuit. As you can imagine, the transmission's operational characteristics can be drastically altered and also customized to the given application through modifications to this component.
Because there are no commercially available shift kits for these transmissions, we began working on valve body modifications that were appropriate for Supras, Jeeps with the AW4 transmission, Toyota Tundra, Tacoma and 4Runner, and also Lexus SUV's and rear drive passenger cars- especially those that needed to handle the additional power that accompanies the installation of a supercharger, turbo or nitrous oxide injection.
At the risk of oversimplification, there are a few things that are done in concert to create much more favorable operation of the gearbox. The first thing that needs to be done is to increase the hydraulic operating pressure of the transmission- this pressure is known as "line pressure". All hydraulic functions of the transmission are based on this pressure- what is especially of concern for these purposes is the clamping force which is applied to the clutches and bands to get them to hold against engine torque.
In simple terms, increased engine output is complemented by increased line pressure and increased "clamp" on the clutches- this can be likened to a performance clutch with a heavier pressure plate spring in a manual transmission equipped vehicle.The idea is to raise this pressure only slightly at light throttle but increase it by 30-40% at full throttle- where it is really needed. The effects of this are shifts that are not overly uncomfortable at lower throttle openings, while at heavier throttle, firm shifts with much shorter clutch application time and increased clamping force can be achieved. An additional benefit of this is increased flow through the transmission's cooler and lube system.
Secondly, hydraulic pressure is normally routed through an orifice in a metal "separator plate" that resides between the two halves of the valve body before it gets to its intended destination. By altering these orifices, we can increase the volume of hydraulic oil that is used to apply the various clutches and bands.
The final part of modification is the alteration of the accumulator circuits. These are hydraulic circuits that are parallel to the components that are used for shifting. Their function is to absorb or "accumulate" some of the hydraulic pressure that is intended to apply a clutch pack or band. By limiting the action of what is essentially a "shock absorber" for each shift, we are able to further reduce clutch lock up time and shift lag at wide open throttle.
The end result is that shift time is reduced by 30 to 80%, depending on the amount of acceptable shift feel and the intended application. The clamping force that is required to apply the clutches and bands is increased by 30 to 40% at full throttle. Flow through the cooler and lube circuit is increased and the converter clutch application time is also reduced.Transmission and valve body upgrades are not only for American made vehicles anymore. Increased performance and more efficient shifting is now available for vehicles of almost every manufacturer thanks to the few companies that are willing to do the research and development work required for this rapidly growing segment of the automotive aftermarket.
For more information, please follow this link:
Toyota High Performance Transmissions
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
About The Author
John Lombardo, a.k.a. Transdude, is co-owner of IPT Performance Transmissions and has been in the transmission and high performance industry for over 20 years. Visit his website- http://www.importperformancetrans.com for more drivetrain information articles.
**This free reprint article is available for use in ezines,
forums, websites and blogs on the condition that the article
is not altered and the resource box remains intact with all
hyperlinks activated.
AW4 Valve Body Installation Instructions
-John
Last edited:
GrimmJeeper
NAXJA Forum User
- Location
- Gardena, CA
Thanks for posting this :cheers:
wolfpackjeeper
NAXJA Forum User
- Location
- 500' and 500KCAS, RAF lakenheath
http://supraforums.com/forum/showthread.php?t=267655
this is a link to a valve mod I had handy, good pictures
this is a link to a valve mod I had handy, good pictures
That's been around for a while but just jamming some washers under your accumulator pistons is not a valve body mod or a very good idea.
-John
wolfpackjeeper
NAXJA Forum User
- Location
- 500' and 500KCAS, RAF lakenheath
yea, didn't say I used it, just have it handy. I have not had a reason to mess with mine even after the stroker. Does have some decent internal pictures though.
chrslefty
NAXJA Forum User
- Location
- centeral phx az
would it be a good idea to also incress the number of clutch packs if one were to do this mod while having the tranny rebuilt ?
Absolutely, we add quite a few more during our performance rebuilds.
Our rebuild kits also come with everything needed to add the extra clutches as well.
-John
