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Discussion Starter · #1 ·
i have an 06psd with the sct tune from ID. I have the WOT shift pressure set to -10 on all the shifts. But got to thinking, and was wondering if it is better for the tranny to have a firmer shift or to let it slip a little and have smoother shift. I am just looking after the longivity of my tranny. Also has anyone messed with the pressure and speed for the best ET.
 

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I backed off on the pressure for mine and my tranny shifted like crap! So I switched it back. I have always heard that a tranny should "hit" the next gear, not slide into it.
 

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Guys,

One thing to remember here is that anytime the transmission is shifting to another gear, whether it be upshifting or downshifting, the clutches for that gear are slipping. What happens is the pressure that is pushing against that clutch pack releases, thus allowing them to slip/slide within their respective steels. The quicker the shift, the less time that the clutches are slipping. Idealy, no slip would be the best thing for the longevity of the clutches. When you have the ability to adjust the shift time/shift hardness, it is best to have a quicker, firmer shift. The slight jolt you feel is the shorter shift time, with its side effect being what some people call a harder shift. As long as the tires aren't chirping at each shift, you really aren't putting excess strain on the drivetrain. Some people say that U-joints seem to go out quicker, but I have found out that that is mainly because of other factors effecting the longevity of the U-joints themselves, with the major contributing factor being the size of tire (running oversize tires with factory gearing) and the pinion angle being at too much of an offset.

The current strategy for the TorqShift tranny has the FICM defuel the engine during each shift so that there is less power on the clutches while they are performing the shift. In essence this applies less rotational pressure, which reduces friction, to the clutch pack performing the shift. The result is longer clutch life.

The only other time that they slip is when too much power is applied and the friction between the clutches and steels is overcome by that excess power. This slipping is not intended and is not considered normal.

When I build/re-build trannies for my customers, I advise them to let me put in a shift kit for this purpose, even for stock applications. Many times, dependent on the brand of transmission, I can make them have a relatively quick shift event that is transparent to the driver. There is not hardly any head-jerking, but the shift is noticeably quicker. My main feedback after the tranny has been ran for awhile is that I could have made the shift even quicker, even to the point that they can feel the "jerk". Now I will additionally ask the customer if they mind a little "jerk" during each shift, and 99% of the time, they say "Go ahead."

This applies to WOT shifts more so, because that is when you will be getting the maximum power (in theory) from the engine. I would set the shift firmness as high as you can stand it. As far as your ET is concerned, and in my experience, the quicker the shift, the lower the ET will become. I hope this helps.

Later,
 

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Guys,

One thing to remember here is that anytime the transmission is shifting to another gear, whether it be upshifting or downshifting, the clutches for that gear are slipping. What happens is the pressure that is pushing against that clutch pack releases, thus allowing them to slip/slide within their respective steels. The quicker the shift, the less time that the clutches are slipping. Idealy, no slip would be the best thing for the longevity of the clutches. When you have the ability to adjust the shift time/shift hardness, it is best to have a quicker, firmer shift. The slight jolt you feel is the shorter shift time, with its side effect being what some people call a harder shift. As long as the tires aren't chirping at each shift, you really aren't putting excess strain on the drivetrain. Some people say that U-joints seem to go out quicker, but I have found out that that is mainly because of other factors effecting the longevity of the U-joints themselves, with the major contributing factor being the size of tire (running oversize tires with factory gearing) and the pinion angle being at too much of an offset.

The current strategy for the TorqShift tranny has the FICM defuel the engine during each shift so that there is less power on the clutches while they are performing the shift. In essence this applies less rotational pressure, which reduces friction, to the clutch pack performing the shift. The result is longer clutch life.

The only other time that they slip is when too much power is applied and the friction between the clutches and steels is overcome by that excess power. This slipping is not intended and is not considered normal.

When I build/re-build trannies for my customers, I advise them to let me put in a shift kit for this purpose, even for stock applications. Many times, dependent on the brand of transmission, I can make them have a relatively quick shift event that is transparent to the driver. There is not hardly any head-jerking, but the shift is noticeably quicker. My main feedback after the tranny has been ran for awhile is that I could have made the shift even quicker, even to the point that they can feel the "jerk". Now I will additionally ask the customer if they mind a little "jerk" during each shift, and 99% of the time, they say "Go ahead."

This applies to WOT shifts more so, because that is when you will be getting the maximum power (in theory) from the engine. I would set the shift firmness as high as you can stand it. As far as your ET is concerned, and in my experience, the quicker the shift, the lower the ET will become. I hope this helps.

Later,
So I have the option for -25, -20,-15,-10,0,10,15,20,25
What do you recommend I set it at?
 
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