Want to incorporate some engine braking on drop throttle down hills, nothing crazy just some amount.
Short version; Only at ?closed? throttle does the PCM not shift the trans as programmed, any throttle position greater than closed and the transmission follows exactly as programmed.
Is there a setting in the PCM that overrides the commanded gear shift when the throttle is closed/zero effectively ignoring the shift points as programmed? (Same behavior when trans is in ?TOW/HAUL? mode, at closed throttle it does not follow what is commanded).
The details; Adjusted trans shifting properties to not allow 4th gear below 49mph on upshifts and down shift out of 4th whenever drops back below 45 MPH, these adjustments took effect and function flawlessly, EXCEPT at closed throttle, 0% throttle, regardless of vehicle speed. Trans wont make the shift automatically though while logging during testing the scanner ?says? it is doing just as I programmed yet the transmission is not actually shifting down, though if I manually shift the shift lever from D down into 3rd it then actually shifts into third, (manually shifting at closed throttle works, programmed shifting at closed throttle does not). This anomaly only happens at closed throttle, all other throttle positions the trans behaves as programmed. Scan shows this as well, note at above 60MPH when the throttle is dropped, (0% throttle), the ?Selected Gear? shows a shift down from 4th into 3rd, though the trans is actually still in 4th, (note the RPM didn?t rise to correspond with ?selected gear? when it changed. A little later I manually shift the lever from D down into 3rd and the trans does shift down shift into 3rd, note the rise in RPM and the corresponding increase rate of declaration).
In short while logging with the scanner the ?Selected Gear? reflects all up shifts and down shifts as I programmed whether I am shifting it manually with the shift lever or just letting it shift automatic, the ONLY exception is at ?closed? throttle, the down shift is called out but does not actually take place unless I manually shift the shift lever, it ?indicates? what I programmed and intended it would do yet the trans is not physically making that shift unless I manually shift from D into 3rd. (repeating myself now, part of getting older... )
What am I missing here? A setting that overrides the commanded gear shift when the throttle is closed?
Paul