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Service bulletin 21NA199

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 id10207911
Published by NHTSA2022-02-14
Manufacturer's number21NA199
Manufacturer's date2021-12-10
NHTSA componentPOWER TRAIN; POWER TRAIN:AUTOMATIC TRANSMISSION:FLUID/LUBRICANT:VALVES/VALVE BODY

NHTSA's summary

This informational bulletin advises the technician to replace the TBV if the transmission has any type of repair even if no problem was found, to replace the tbv.

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, Automatic transmission

Vehicles listed
CADILLAC ESCALADE2016, 2017, 2018, 2019, 2020
CADILLAC ESCALADE ESV2016 (the catalog's model; the bulletin names a series or trim of it)
CADILLAC ESCALADE ESV2017, 2018, 2019, 2020
CHEVROLET EXPRESS2021
CHEVROLET SILVERADO 15002016, 2017, 2018, 2019 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SILVERADO 15002021 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SILVERADO 25002016, 2017, 2018, 2019 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SILVERADO 35002016, 2017, 2018, 2019 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SILVERADO 45002019 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SUBURBAN2016, 2017, 2018, 2019, 2020
CHEVROLET TAHOE2016, 2017, 2018, 2019, 2020
GMC SAVANA2021
GMC SIERRA 15002016, 2017, 2018, 2019 (the catalog's model; the bulletin names a series or trim of it)
GMC SIERRA 15002021 (the catalog's model; the bulletin names a series or trim of it)
GMC SIERRA 25002016, 2017, 2018, 2019 (the catalog's model; the bulletin names a series or trim of it)
GMC SIERRA 35002016, 2017, 2018, 2019 (the catalog's model; the bulletin names a series or trim of it)
GMC SIERRA DENALI2016, 2017, 2018, 2019 (the catalog's model; the bulletin names a series or trim of it)
GMC YUKON2016, 2017, 2018, 2019, 2020
GMC YUKON XL2016, 2017, 2018, 2019, 2020

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

Recalls for the same vehicles and component
26V0830002026-02-12. POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE:SOFTWARE; POWER TRAIN:AUTOMATIC TRANSMISSION:FLUID/LUBRICANT:VALVES/VALVE BODY
24V7970002024-10-24. POWER TRAIN:AUTOMATIC TRANSMISSION:FLUID/LUBRICANT:VALVES/VALVE BODY; POWER TRAIN:AUTOMATIC TRANSMISSION:CONTROL MODULE:SOFTWARE

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
17-NA-0662023-07-25. Service bulletin. This service bulletin provides information for automatic transmission Oil Cooler Flush and flow test.
PIP5926A2023-07-17. Service bulletin. This Preliminary information communicates that the t-case input seal, and/or the o-ring most likely is the source of the leak between the transmission and the t-case.
PIP5853C2023-05-15. Service bulletin. This PI communicates to dealers and technicians a possible diode issue in the TCCM, and how to properly diagnose for a diode issue.
16-NA-1302023-03-08. Service bulletin. This service bulletin provides information for after installation of a replacement upper valve body, the transmission may have no Reverse and no 2nd gear.
N2223808402022-11-17. Service bulletin. General Motors has decided to conduct a Voluntary Emissions Recall on certain vehicles with a 6.6L engine (RPO L8T). The Transmission Control Module (TCM) in these vehicles may have been service reprogrammed with incorrect calibrations. If this occurred, the transmission shift quality and timing could be degraded. Dealers are to reprogram the TCM.
PIP5621C2022-10-17. Service bulletin. This Preliminary information communicates to the dealer technician that TAC recommends the utilization of the GDS2 software to aid in diagnosing automatic transmission concerns. TAC is requesting the GDS2 session logs be sent in before the dealer contacts TAC.
22NA0222022-06-21. Service bulletin. This Informational bulletin advises the technician of a possible oil leak at the front cover and how to diagnose it to verify if it is coming from the seal or not.
N1821953802022-05-31. Service bulletin. Service Update. Certain vehicles equipped with a 10-speed transmission may have a condition where the downshift becomes firm after extended highway driving.
183672022-05-31. Service bulletin. Customer Satisfaction. Certain vehicles, equipped with the 10-speed automatic transmission (RPO MF6), may have a condition in which the transmission manual shaft pin was not seated properly. If the shaft pin were to migrate out of position, the driver may find they cannot shift the vehicle into any gear other than the last one selected. The customer may be unable to return the vehicle back to park, in which case they would be required to engage the parking brake to ensure the vehicle does not roll from its intended position. Dealers will replace the transmission manual shaft pin. Private Message sent to select dealers.
PIP58342022-03-14. Service bulletin. This Preliminary information communicates that the service 4wd message related to C119E is under investigation for a repair.