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Service bulletin 21-NA-138

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 id11004990
Published by NHTSA2024-07-20
Manufacturer's number21-NA-138
Manufacturer's date2024-07-09
NHTSA componentSUSPENSION

NHTSA's summary

This service bulletin provides a repair procedure to correct a customer concern of a Squeak, Grind or Clunking Noise from Rear Leaf Springs.

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

Suspension

Vehicles listed
CHEVROLET SILVERADO 25002015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024 (the catalog's model; the bulletin names a series or trim of it)
CHEVROLET SILVERADO 35002015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024 (the catalog's model; the bulletin names a series or trim of it)

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

Recalls for the same vehicles and component
20161902016-04-28. Suspension
16V2560002016-04-28. SUSPENSION:FRONT:CONTROL ARM

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
25-NA-1522025-11-15. Service bulletin. this bulletin advises the tech not to replace the shock for possible air leak, but to replace the air valve on the shock.
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.
05-03-07-009L2025-03-08. Service bulletin. This service bulletin provides information on Wheel Alignment Specifications, Requirements and Recommendations for GM Vehicles.
19-NA-1292025-03-05. Service bulletin. This technical bulletin provides repair information to correct a customer concern of a squeak and/or clunking noise coming from the rear of the vehicle.
21-NA-1382025-02-19. Service bulletin. This service bulletin provides a repair procedure to correct a customer concern of a Squeak, Grind or Clunking Noise from Rear Leaf Springs.
PIT6304A2025-02-03. Service bulletin. This Preliminary information communicates a diagnostic Aid from root causing DTC: C1197 sym 92 caused by a pinched air inlet hose to the suspension compressor air leveling system.
PIT63042024-12-17. Service bulletin. This Preliminary information communicates a diagnostic Aid from root causing DTC: C1197 caused by a pinched air inlet hose to the suspension compressor air leveling system.
PIT62552024-12-05. Service bulletin. This Preliminary information communicates a diagnostic tip when experiencing an error when trying to perfom a trim height learn or review pressure data in GDS
19-NA-1292024-10-17. Service bulletin. This technical bulletin provides repair information to correct a customer concern of a squeak and/or clunking noise coming from the rear of the vehicle.
05-03-08-002J2024-09-20. Service bulletin. This service bulletin provides information to dealership personnel on diagnosis and replacement of shock absorber and strut due to fluid leak.