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Rob D

Transmission Learning?

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Hey Guys,


I've been sending some issues with transmission programming up to Brian, but wanted to run my theory passed you all for comment.


I've been trying to move the 4th gear and TCC lock point up to a higher speed in tow haul mode. The issue I run into is that the truck will sometimes follow the new program and others it will revert back to stock shiftpoints. It does seem to be getting better though and shifting where I want more frequently.


My theory is that the trans has some sort of PID/learning ability that we don't have access to. If this were the case, and the PID values are not set by the curves available in UDC Pro; but always start out near the stock shiftpoints it would sort of explain what I'm seeing as the truck has to learn away from stock and towards the curves I set to shift where I want...


What do you guys think? Brian feel free to weigh in also!

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I've been fighting this for a long time. I have found that TCC lock up will move consistently for me but 4th gear only does at certain throttle percentages. For my 2005 when I run at 20% throttle my truck holds the shift point, if I hit 23-24% it shifts at 48-50mph at a stock shift point.


What I found yesterday was very interesting. I reset truck to stock software (typically i run SW 5/TQ 3/Timing 1) with my camper on. What i immediately noticed is that I was using far more throttle to get moving and keep moving, in the 35-40% range from my typical 20-30% with Revo software running. The shifting of my truck was perfect, it held 4th and lock up until 55-60 and in tow haul down shifted then locked 3rd and held at 55-60mph up a hill where before it would continuously try to downshift.


What this looks like to me is that either the Revo software does some sort of change to throttle percentage or shifting (unlikely) or that the stock software of the truck doesn't handle increased power and thus less throttle percentage. It also appears that when modifying the rpm in UCD Pro it's not a straight adjustment but figures that plug into some stock algorithm that doesn't handle those changes consistently.


My current plan to try and get where i want is to try to trick throttle percentage. I haven't quite figured that out and am not sure if just adjusting the TTVA down will accomplish it. I'll post back with success if I find it!

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The revolution software mostly adds timing to the stock duration from what I've seen. Either way you make more power with less pedal so your findings make sense. I experimented briefly with decreasing the duration in hopes of using more pedal and improving shifts. I was towing on a trip and ran into some glitches and had to go back to a revolutionary tune. When you change duration you also have to remap all the timing. Maybe I'll take another cracking at it.

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