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Low speed shifting feeling like clutch dump

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I will make one calibration change for an additional $100 per change. For example, changing a shift point for a given gear is $100 vs changing a shift point and a pressure setting would be $200. That value can be used towards the full custom tuning price.

 

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Galvatron9999
Low speed shifting feeling like clutch dump

I've been working through rough 1-2 and 2-3 upshifts at light throttle (100-180 Nm). So far I've:

  • Reduced oncoming volume preset (55 to 21) - big improvement
  • Disabled Discrete Shift Torque on 1-2 and 2-3 - big improvement, the TCM was seeing 0 or 300 Nm instead of actual torque so the base pressures were way off

It's a lot better than where I started but the 1-2 still feels like a clutch dump. When I graph the pressure during the shift the oncoming pressure just steps up almost vertically, there's no ramp to it at all.

I know you've said not to mess with transition/inertia factor. Is there something else I should be looking at to smooth out that pressure ramp at low torque? Or is there a case where adjusting the initial transition time is ok for a truck/tow application that doesn't need fast shifts? What kind of signals in the logs represent a "clutch dump" kind of feel?

I'm leaving TCC unlocked pretty often to reduce heat.

 

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