Service bulletin 21-039-14

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

NHTSA's summary

Flash: Transmission Shift Enhancements This bulletin involves reprogramming of the Transmission Control Module (TCM) with the latest available software. The following TCM calibration improvements are available for vehicles equipped with the 845RE 8 speed transmission (sales code DFL) or 8HP70 8 speed transmission (sales code DFD or DFK). These improvements are listed per engine application.3.0L gas engine (sales code EHD) Improved upshift timing. Improved torque converter engagement. Improved shift timing during tow mode operation. Improved shift points during aggressive driving. Calibration improvement to correct bump feel during 2-1 downshift. Improved shift timing while in snow, base, and hill modes.3.6L gas engine (sales code ERB) Improved 4-3 and 3-2 downshifts. Improved shift timing at higher altitudes. Improved shift timing while in sand mode. Calibration improvement for multi-gear downshift timing during passing maneuvers. Calibration improvement for intermittent delayed upshift.5.7L gas engine (sales code EZH) Improved upshift timing in eco, base, and hill modes and while using cruise. Improved 8-7, 3-2, and 2-1 downshift timing Improved shift timing at higher altitudes. Improved torque converter engagement.

The document

• NHTSA's copy of the document (PDF)
• If that address does not open, try this one

The document is the manufacturer's. This site does not hold it. NHTSA files a document at one of these two addresses; we have not asked NHTSA which.

Components

Electrical system, Fuel system, Transmission and driveline

Listing a model year does not mean every vehicle of it is concerned: the document says which.

A recall listed here may apply to some of the same vehicles. Only the manufacturer can say whether it applies to one vehicle.

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