The problem is that the original calibration is engineered for driver comfort rather than ultimate component is used as strength. The soft, sliding shifts that are part of the original design are not appropriate for use, the trailer increasing horsepower, use the road, racing, etc.
These calibration inadequacies quickly manifest themselves as extremely poor quality of the change, and often, severe damage to the gearbox is soon to we have follow. One of the most common symptoms of this is the engine stuttering or hitting the revolution limiter during a full throttle upshift.
Without getting in into too much technical detail, the factory defaults can be treated with the modification and recalibration of the control valve assembly, AKA the valve body.
The valve body is as called as or we can say as component that is comprised of valves, solenoids, an orifice separator plate and an intricate series of steps which is the most complex part of the more complex of the automatic transmission vehicle.
The function of the valve body is to act as the "brain" of the automatic transmission that directs hydraulic pressure to the appropriate clutches and bands at the right time to initiate upshifts, down changes, backward selection, using clutch converter, etc.. as well as the timing of the change control and quality of change, is also responsible for directing hydraulic pressure to the cooler and the lubrication circuit.
As we you can imagine or you can say, the transmission's operational characteristics can be drastically altered and also customized to the given application with modifications to this component.
Because there is no commercially available kits of change for these transmissions, we began working on valve body modifications that were appropriate for Supras, Jeeps with the AW4 transmission, Toyota Tundra, the Tacoma and 4Runner, and also Lexus SUV and rear passenger car drive handle especially those requiring additional energy accompanying the installation of a supercharger, a turbocharger or a nitrous oxide injection.
At the risk of oversimplification, there are some things that are done in concert to create a much more favorable operation of the gearbox.
The first thing that needs to be done is to increase the operating pressure of the hydraulic pressure transmission is called "line pressure". The hydraulic functions of / or the transmission are based on this pressure which is especially of concern for these purposes is the clamping force applied to the clutches and bands to get them hold against engine torque.
In simple words we can say that, increased engine output is complemented by increased line pressure and the "rising clamp" on the clutches that can be compared to a performance clutch spring plate with a lot more pressure on a manual transmission 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 changes that have not completed uncomfortable in lower openings of the throttle, while a heavier throttle, the signature changes to a much shorter time using the clutch and increasing the strength strengthening Clamp can be achieved.
An additional advantage of this is increased through the cooler and transmission lubrication system.
Secondly, the hydraulic pressure is normally routed through a hole in a metal "separator plate" which resides between the two halves of the valve body before it gets to its intended destination. Altering these holes can increase the volume of hydraulic oil which is used to apply the various clutches and bands.
The final part of modification is the alteration of the accumulator machine or we can say circuits. These are hydraulic circuits that are parallel to the components that are used to shift. Its function is to absorb or "accumulate" some of the hydraulic pressure that is intended to implement a package or a bandage clutch. By limiting the action of what is essentially a "shock absorber" for each shift, we can further reduce the time we lock up clutch and we shift the delay in throttle.
The end result is that the time of the change is reduced by 30 to 80% depending on the amount of shift feel and acceptable to the intended use. The clamping force required to apply the clutches and bands is increased to 30 to 40% full throttle. Cross the cooler and lube circuit increases and the time of use converter clutch is also reduced.
Improvements transmission body and valve are not only for American made vehicles more. The 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 work of research and development required for this rapidly growing segment of the sold off or after all.