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The way I understand it, the mechatronics constantly talks to the DME and controls the shifting based on various data from the DME. Things like coolant temp, load, rpm, throttle position, etc. are used to determine how fast the shifting needs to be, how hard, and how much overlap is to be used. Terry seems to have figured out a way to tell the mechatronics what it wants to hear to make the shifts as fast and forceful as they can be every time. So he hasn't flashed the mechatronics, but his DME flash tells the mechatronics how it should shift.
Originally Posted by Sikh335
This could be very beneficial with an upgraded valve body because the mechatronics is constantly monitoring the shifts, and adjusting it's memory to give the right shifts at the right time based on factory settings. (it measures the time it takes to shift, and the slip ratio which is an indication of overlap, according to documents I've read) What this could mean is that if the valve body is upgraded, the mechatronics could do what it can to actually make the shift less firm and lower line pressure if it feel it needs to.
I've read accounts where someone gets an upgraded valve body in a 5HP or 6HP ZF automatic and notes how hard it shifts, and also notes that over time, the shifting becomes less harsh. This may be the mechatronics adjusting, trying to get the shifts to a more stock-like profile.
A valve body upgrade and Terry's flash could work together to make the transmission shift hard every time, which would be harder than is possible stock because of the upgraded valve body. Faster, harder shifts, less overlap and higher line pressure all lead to less slip, which increases the life of the transmission by keeping the fluid temp down and minimizing wear.