Flash: Transmission Shift Enhancements This bulletin involves flash reprogramming of the Transmission...

Bulletin number

21-026-14

Component

Electrical system

Summary

Flash: Transmission Shift Enhancements This bulletin involves flash reprogramming of the Transmission Control Module (TCM) with new software. Some customers may experience any or all of the following transmission shift concerns. 3-2, 2-1 Shift bump on deceleration. Shift quality during hard acceleration. Excessive shifts during cruise control operation. Intermittent delay shift condition. Engine braking improvements during downhill descent. Manual gear selection improvements at higher altitudes. Drivability improvements in 4 low. Hesitation improvements. Inconsistent and/or harsh 1-2, 2-3, 3-4, 4-5 upshifts at moderate throttle. Inconsistent and/or harsh lift-foot upshifts. Inconsistent and/or harsh coasting 3-2, 2-1 downshifts in Hi or Lo range. Ratio fault detection during 1-2 upshift or 8-7 downshift. Grade hunting (repeated shifting while ascending a grade). 8-7-8 shift busyness when approaching max vehicle speed. Undesired gear selection at high altitude. Undesired gear selection when driving downhill (not enough powertrain braking). Time to exit TIP (manual/paddle shift mode) takes too long. Unintended downshifts driving at certain speeds. 4-3 coasting downshift may cause excessive engine noise during engine braking. Shift hanging when vehicle is started cold. Undesired shift toggling in Manual/Paddle Shift mode. Lo range selec-speed control 1-2 shift busyness.

Owners of these vehicles have filed 485 complaints in the electrical category.