Chevrolet Silverado 2500 2020–2023 — technical service bulletin
Bulletin 21-NA-120 · NHTSA communication 10227252 · issued Nov 17, 2022
Technical service bulletin
communication type
Power Train
component
2020–2023
model years
16
vehicle entries
Official summary
This service bulletin provides a Diagnostic Tip for Noise, Vibration, and/or Harshness Issues/Clunk Noise Heard During Coast Down Event after the transfer case was removed from the transmission and reinstalled during a recent repair.
Vehicles covered
- 2020 Chevrolet Silverado 2500
- 2021 Chevrolet Silverado 2500
- 2022 Chevrolet Silverado 2500
- 2023 Chevrolet Silverado 2500
- 2020 Chevrolet Silverado 3500
- 2021 Chevrolet Silverado 3500
- 2022 Chevrolet Silverado 3500
- 2023 Chevrolet Silverado 3500
- 2020 GMC Sierra 2500
- 2021 GMC Sierra 2500
- 2022 GMC Sierra 2500
- 2023 GMC Sierra 2500
- 2020 GMC Sierra 3500
- 2021 GMC Sierra 3500
- 2022 GMC Sierra 3500
- 2023 GMC Sierra 3500
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.