I have never had a problem like this before. In normal D position of the shifter, the transmission will upshift at wot or close to wot, when I let off the throttle say in 5th gear the transmission will upshift to 6,7,8,9, 10. Basically it will do what you would think based on throttle input. If I put the shifter in Sport mode, it will drive normal, feels better and extends shifts further. The problem is going WOT or getting close to WOT the car will downshift accelerate and shift on point. What ever gear your in when you let off the throttle it will hold and never upshift. Even if you start applying throttle, it will just stay in that gear. The pcm will continue to hold that gear as commanded and only downshift as the vehicle slows down. Never an upshift until the car comes to a stop and the transmission goes into first or you shift to D and then back to S. Then it will upshift every gear or downshift on point perfectly until it goes WOT. This only happens in S mode, never in D. Everything in a datalog looks the same between D or S, no codes no other issues. Another thing I have noticed is that changing between D and S mode only changes SST mode from unknown 3 to unknown 4. Shift map and shift scheduling stay the same and they definitely are different, with different shift rpms, feel and gear skipping up and down. My 2020 Shows different shift map and map scheduling when moving the shifter around and has non of these issues. If someone could look over the calibration and two logs, I would greatly appreciate it.
Mike, I looked into the backout time and everything was stock. I changed to the backout for sport to the base/drive and it helped some what. Part throttle, getting into boost when I let off it will now upshift all gears. Wide open throttle it will now upshift gears when I let off the throttle but will do random things. The most common now will be to let off in 5th gear at wot and it will upshift to 6,7 and 8. However almost immediately will downshift back to 7 and then after a few seconds downshift to 5th. It will hold 5th and at some point finally upshift to all other gears. None of this happens in Drive, just sport mode and I have tried making every setting use drive and it still shifts as in sport. Everything in sport is great just this hang up after wot. I even set every transmission setting to stock and have this problem. Yesterday I spent about four hours playing with this problem and my last pull of the night I had a different issue but better, I let off in wot in 5th, it shifted 6,7,8. as soon as 8th was the current gear it shifted back to 7th and stayed in 7th for about 10 sec and then went 8,9.
What about the coastdown tables? The upshift, downshift, and coastdown tables all have to work together. I tried modifying these but ultimately found the best results by copying the 2021 tables into my 2018 cal.
Is this with paddles active and gear number on the dash, or deactivated and no gear showing on the dash? If paddles are active hold upshift 2-3 seconds to deactivate. Mine when active manually holds all the gears unless decelerating and getting below a certain speed threshold it will shift to 2nd or 1st. The shift schedules can get very squirrly very quickly when making changes.
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