


Quick debrief on the first DMJKB52/GUB transmission relearn. This is the working tune I rebuilt myself.
After flashing the native GUB firmware, programming the correct solenoid-body strategy and clearing the transmission adaptives, I ran the stock transmission calibration with only VFS_PRS_MAX changed from 110 to 132 psi across all seven VFS rows.
I drove for about 40 minutes. The recorded section was 12 minutes 14.5 seconds. I intentionally did not go WOT because the transmission was clearly still improving throughout the drive.
Log summary:
-Maximum APP (applied pedal position)was 44.5%, maximum engine speed was 4,620 rpm and maximum air load was 1.396.
- TFT increased normally from 173.4°F to 185.3°F.
- All six forward gears were used with 45 commanded gear changes.
- I did not see another sustained neutral-out or ratio-release event.
- Reverse was still present when I returned home hot, unlike the previous event.
The log also appears to have captured the adaptive learning in progress. Using the commanded 1–2 change until TSS/OSS ratio settled within approximately 1% of the expected 2nd-gear ratio and remained there for 0.15 second, the comparable 1–2 shifts at roughly 14–17% pedal progressed as follows:
1.135 sec
1.136 sec
1.024 sec
1.008 sec
0.944 sec
That downward trend under similar pedal input is strong evidence that the transmission was still learning and reducing the shift completion time. Because of that, I believe avoiding WOT during this drive was the correct decision. I want to give it at least another complete warm driving cycle or two, with repeated normal upshifts and coast-downs, until the shift behavior stops noticeably changing and reverse remains repeatably present hot.
The 132 psi VFS change is definitely active. Shift Solenoid C reached 131.984 psi during the drive, so the controller accepted and used the increased VFS_PRS_MAX value without requiring WOT.
However:
-Shift Solenoids A, B and D each peaked at approximately 109.939 psi.
-Line Pressure Desired reached 299.938 psi
We therefore need to determine whether the approximately 110 psi plateaus represent expected VFS latch behavior or whether another calibration item is still limiting those commands. I do not want to blindly force them higher without understanding the state logic.
Overall, this was a successful diagnostic relearn. The transmission completed repeated shifts, shift completion improved during the drive, the 132 psi ceiling was actually used, and reverse remained present hot. I think the next step should be more normal adaptation time plus exposing the latch and final-pressure information before the first WOT test.
Johnny gave me the green light to scout my OS and make my own definitions that will be useful. Check them, change a pressure and search my file, anything turned red means it’s already available. Present Johnny with a legit XDF file of confirmed working definitions and he will permanently add them to Green Oak 2368k for everyone.