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Service bulletin 18NA379

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.

The communication, as NHTSA indexes it (as of 2026-10-19)
TypeService bulletin
NHTSA id10158830
Published by NHTSA2019-04-22
Manufacturer's number18NA379
Manufacturer's date2019-03-18
NHTSA componentPOWER TRAIN

NHTSA's summary

This technical bulletin provides a procedure to program the TCM to correct the customers concern of a MIL Illuminated, Vehicle wont go above 25 mph and/or 1-2 Shifts feel like a momentary tie up.

The document

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

Transmission and driveline

Vehicles listed
BUICK ENCLAVE2019
CADILLAC XT42019
CHEVROLET TRAVERSE2019
GMC TERRAIN2019

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

Recalls for the same vehicles and component
20205202020-10-29. Powertrain
20V6680002020-10-29. POWER TRAIN:AUTOMATIC TRANSMISSION

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

Other bulletins for the same vehicles and component
PI0281L2025-06-12. Service bulletin. This preliminary informational (PI) bulletin provides information to dealership personnel that may be helpful when addressing underbody component corrosion with customers.
09-06-04-026Z2025-01-23. Service bulletin. This bulletin provides information on identifying Non-GM Engine Calibrations for Gasoline Engines using the Tech 2 or GDS 2.
08-07-30-035I2024-12-19. Service bulletin. This service bulletin provides information on the harmful effects of ethylene glycol in transmission fluid.
21-NA-1812024-12-18. Service bulletin. This service bulletin provides 9th gear operation information to respond to customers that may comment on transmission shift operation.
23-NA-0212024-12-04. Service bulletin. This service bulletin advises the tech that the rotational Clicking Noise Heard After Engine Shut Down may be normal characteristics of the vehicle.
04-06-01-029K2024-12-04. Service bulletin. This informational bulletin explains Unscheduled Supplemental Services and the importance of GM Simplified Maintenance Schedules.
24-NA-2232024-11-19. Service bulletin. This service bulletin informs the technician of an alternate lift procedure that has been developed when the lift plate does not fit the top of the transmission case for 6T30, 6T35, 6T40, 6T45, and 6T50 Transmissions.
20-NA-1382024-11-05. Service bulletin. This bulletin provides information on Policies Applicable to All U.S. Dealers for Engine and Transmission Assembly Replacement Under Warranty, Policy or Customer Enthusiasm and information on Submission of Warranty Transaction in Global Warranty Management.
23-NA-0722024-10-30. Service bulletin. This service bulletin provides a procedure to correct a customer concern of Shudders or Shakes at Low Speeds.
08-07-30-026I2024-10-24. Service bulletin. This service bulletin provides information on some vehicles that may rock or move slightly forward or rearward while in Park at start up after cold soak. This condition may be accompanied by a clunk noise. This is a slight movement that is more often seen visually, rather than felt, when viewed from the outside and using the auto-start feature, if equipped.