Flash: AS69RC/AS66RC Transmission Shift And Diagnostic Enhancements
This bulletin involves reprogramming the Transmission Control Module (TCM) with the
latest available software.
A small number of customers may experience one or more of the following conditions.
Vehicles equipped with an AS69RC automatic transmission (sales code DF2)
? Less than desired towing performance while using cruise control.
? Harsh engagement while shifting from neutral to drive, neutral to reverse, or park to
reverse with vehicle still in motion (rolling garage shift).
? Transmission Oil Temperature light illumination during high engine and tow loads.
? Engine flare during 2-1 tip in downshift.
? Less than desired shift quality during 6-5, 5-4 coasting downshifts.
? Delayed downshifts in Tow/Haul mode while driving down grades.
? Less than desired transmission shift performance when transitioning from low
traction surface to high traction surfaces. (i.e. ice covered road to clear pavement).
? Harsh 2-1 downshift.
? Less than desired shift points during light pedal and Wide Open Throttle (WOT)
operation or while in Tow/Haul and engine brake modes.
? Delayed engagement when shifting from neutral to drive, neutral to reverse, or park
to reverse (garage shifts).
? Audible squawk noise on 4-3 downshift.
? Poor vehicle acceleration in first gear with vehicle fully loaded.
? Malfunction Indicator Lamp (MIL) illumination with no defect found for Diagnostic
Trouble Code (DTC) P253D - PTO Sense Circuit High.
AS66RC automatic transmission (sales code DF3)
? Transmission Oil Temperature light illumination during high engine and tow loads.
? Less than desired towing performance while using cruise control.
? Harsh engagement while shifting from neutral to drive, neutral to reverse, or park to
reverse with vehicle still in motion (rolling garage shift)
? Engine flare during 2-1 tip in downshift.
? Less than desired shift quality during 6-5, 5-4 coasting downshifts.
