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Service bulletins for the 2021 GMC Sierra

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.

1649 on file from NHTSA, as of 2026-10-19.

By type

By component

By trouble code

By topic

Only bulletins with component: Transmission and driveline are shown. Show all

Bulletins, newest first
PIP6008A2024-12-05. Service bulletin. POWER TRAIN. This Preliminary information communicates a possible retainer ring dis-lodged for a DTC P2714, may not have reverse as well.
PIP60142024-12-05. Service bulletin. POWER TRAIN. This Preliminary information communicates for Technicians installing a Service Replacement Transmission Assembly to contact Technical Assistance to make sure unit is not suspect of a snap ring concern prior to installation.
04-06-01-029K2024-12-04. Service bulletin. POWER TRAIN; STEERING; ENGINE. This informational bulletin explains Unscheduled Supplemental Services and the importance of GM Simplified Maintenance Schedules.
N2424544412024-11-27. Service bulletin. POWER TRAIN. Certain vehicles listed above, may have a condition where the transmission control valve has worn, resulting in a gradual loss of pressure within the valve. The effects can cause harsh shifting, setting a service engine soon message, reduced engine performance or P0747 diagnostic trouble code. This special coverage covers the condition described above for a period of 15 years or 150,000 miles (240,000km), whichever occurs first, from the date the vehicle was originally placed in service, regardless of ownership. For vehicles covered by Vehicle Service Contracts, all eligible claims with repair orders on or after November 26, 2024, are covered by this special coverage and must be submitted using the labor operation codes provided with this bulletin. Claims with repair orders prior to November 26, 2024, must be submitted to the Service Contract provider. Vehicle owners or lessees who paid for repairs referenced in this Special Coverage (“Customers”) are eligible for reimbursement of their reasonable and customary expenses in accordance with the procedures specified below. The conditional right to reimbursement is provided by GM solely in the interest of customer satisfaction and is personal to Customers. Customers may not assign and GM does not consent to any assignment of any Customer’s right to submit reimbursement claims, or to receive reimbursement, or any other rights granted by this Special Coverage to any third party, including but not limited to service contract providers, and this Special Coverage is not intended to and does not confer any third party beneficiary, subrogation or contribution rights, or any other rights to reimbursement, against GM, whether in law, equity or otherwise, on any third parties. Dealers are to install a new control valve body. The repairs will be made at no charge to the customer.
20-NA-1382024-11-05. Service bulletin. POWER TRAIN; ENGINE. 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.
21-NA-2752024-10-30. Service bulletin. WHEELS; SERVICE BRAKES; POWER TRAIN. This service bulletin provides repair information to correct customer concerns of Rear Wheel Lock Up, ABS Event, Loud Bang and a Flashing “D” on Driver Information Center (DIC) when Lightly or Moderately Accelerating Forcing an 8-7 or 8-6 Downshift.
21-NA-1202024-10-24. Service bulletin. POWER TRAIN. 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.
08-07-30-026I2024-10-24. Service bulletin. POWER TRAIN. 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.
23-NA-1422024-10-17. Service bulletin. POWER TRAIN. This technical bulletin provides a procedure for the techs to replace the forward check ball and separator plate if found the cause of the customers concern of No Forward Gear When Shifting from Park to Drive and/or Reverse to Drive.
22-NA-1822024-10-17. Service bulletin. POWER TRAIN. This service bulletin advises the technician to check if the transmission cooler lines are twisted to correct customer concerns of Harsh Shift, Shudder, Surge, Stall, Transmission Overheating and/or High Transmission Fluid Temperature.
PIP6000A2024-09-14. Service bulletin. POWER TRAIN. This Preliminary Information communication advises the technician on a parts restriction on the Generation I 8 speed rear wheel drive valve bodies.
PIP5996A2024-09-13. Service bulletin. POWER TRAIN. This Preliminary information communicates diagnostic information for vehicles with transmission noise.
PIP59962024-09-11. Service bulletin. POWER TRAIN. This Preliminary information communicates diagnostic information for vehicles with transmission noise
PIP59922024-09-06. Service bulletin. POWER TRAIN. This Preliminary information communicates the results if an in-correct P/N Stator Shaft Support was installed during a transmission repair attempt.
23-NA-1422024-08-16. Service bulletin. POWER TRAIN. This technical bulletin provides a procedure for the techs to replace the forward check ball and separator plate if found the cause of the customers concern of No Forward Gear When Shifting from Park to Drive and/or Reverse to Drive.
24-NA-1412024-08-15. Service bulletin. POWER TRAIN. GM is receiving damaged (cracked or broken) transmission cores returned to the reman facilities. The damage is being caused either in the removal process by the technician, or inadequate packaging or shipping. This bulletin advises the dealers to be more careful not to damage the transmissions during removal and to package the core properly for return.
PIP5926C2024-08-13. Service bulletin. POWER TRAIN. 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.
23-NA-1422024-07-31. Service bulletin. POWER TRAIN. This technical bulletin provides a procedure for the techs to replace the forward check ball and separator plate if found the cause of the customers concern of No Forward Gear When Shifting from Park to Drive and/or Reverse to Drive.
21-NA-2382024-07-31. Service bulletin. POWER TRAIN. This technical bulletin provides a procedure to inspect the front pump of the transmission for a possible leak.
99-04-20-002O2024-07-30. Service bulletin. POWER TRAIN. This service bulletin provides information on Driveline Clunk Noise and what is acceptable and what is considered normal operation.
16-NA-0192024-07-23. Service bulletin. POWER TRAIN. This service bulletin provides information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flares.
22-NA-1822024-07-09. Service bulletin. POWER TRAIN. This service bulletin advises the technician to check if the transmission cooler lines are twisted to correct customer concerns of Harsh Shift, Shudder, Surge, Stall, Transmission Overheating and/or High Transmission Fluid Temperature.
21-NA-2382024-06-18. Service bulletin. POWER TRAIN. This technical bulletin provides a procedure to inspect the front pump of the transmission for a possible leak.
23-NA-1422024-06-18. Service bulletin. POWER TRAIN. This technical bulletin provides a procedure for the techs to replace the forward check ball and separator plate if found the cause of the customers concern of No Forward Gear When Shifting from Park to Drive and/or Reverse to Drive.
19-NA-1362024-06-08. Service bulletin. POWER TRAIN. This service bulletin provides a diagnostic procedure to aid in correcting a customer concern of a Howling, Whining/Whirring Noise, Shudder/Vibration and/or Grinding Noise While in 4HI, 4HI Auto and/or During Parking Lot Maneuvers in Auto Mode.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.