Service bulletin 21-004-13

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: Drivetrain Control Module (DCTM) - Transfer Case Operational Enhancements This bulletin involves flashing the Drivetrain Control Module (DCTM) Owners may indicate that they have experienced one or more of the following symptoms: Moaning or groaning noise while coasting and/or during a very light acceleration around 5 to 8 mph (8 to 13 kph). The SERV 4WD message appears and the vehicle shifts from 4WD to 2WD. Binding of the front driveline while turning on steep grades at speeds around 3 to 5 mph (5 to 8 kph).Surge/Shudder at speeds greater than 50 mph (80 kph).

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, Engine, Transmission and driveline, Transfer case

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

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