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I was wondering if one were to increase the line pressure sent to the clutch packs/bands on an A/T would that increase the torque capacity of said transmission? I figure it would because it would decrease amount of time needed for clutches to grab and thus reducing any possibility of slippage/heat?

Furthermore, would adding an ATF cooler also allow for the tranny to be pushed beyond its stock torque limit as it seems the only thing keeping it from handling anything is slippage which can be reduced by keeping the fluid cooler and engaging the clutches firmer.

  • Hello. Welcome to stack exchange exchange for motor vehicles. here's a link to the tour that tells you about how the site works. mechanics.stackexchange.com/tour Again, welcome and Happy New Year. Thanks for the contribution of your question! – DucatiKiller Dec 30 '15 at 20:22
  • Also, if you put in the make model year of your car you will get more specific response. If this is simply about theory, then no need. Take care. – DucatiKiller Dec 30 '15 at 20:23
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Theoretically yes, practically it's not that easy. Line pressure is just one of the components that contribute to the torque capacity of the transmission.

First, it's not the speed of the application of a clutch but the holding strength once the clutch is applied that contributes to strength. In this respect higher line pressure will give higher torque capacity. There are limits though. First you can jack the pressure sky high but if the seals fail because they can't hold the pressure then your up a creek anyway. Next there is a limit to the strength of the clutches and clutch material. There could be lots of pressure but the clutch material fails then your up a creek. If there is lots of pressure and the clutch material holds but you rip the splines out of the clutch disks... With transmissions it's all bout knowing where the weak links of the transmission are and improving the weakest links without running into the next weak link.

Most (not all) of the heat in the transmission comes from the torque converter. As you put more torque through a torque converter it will make more heat. The transmission fluid also works as coolant for other parts of the transmission. If your cooler can't reject the heat fast enough then the components that need cooled will overheat. In this respect the additional cooler will help but it has no direct effect otherwise.

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    It's of use to note that heat is the bane of every automatic transmission. While the tranny cooler will probably not provide any further torque carrying capacity, it will definitely help with longevity under normal conditions. I think that's what you were trying to get at, anyway. – Pᴀᴜʟsᴛᴇʀ2 Dec 31 '15 at 2:40

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