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Service bulletins for the 2021 Chevrolet 4500XD

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.

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

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By component

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

Bulletins, newest first
17-NA-0502025-02-28. Service bulletin. POWER TRAIN; ELECTRICAL SYSTEM; ENGINE. This service bulletin explains how a health report is required when doing repairs on MD LCF vehicles.
08-07-30-035I2024-12-19. Service bulletin. POWER TRAIN. This service bulletin provides information on the harmful effects of ethylene glycol in transmission fluid.
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.
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.
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.
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.
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.
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.
08-07-30-035H2024-06-07. Service bulletin. POWER TRAIN. This bulletin provides information on the harmful effects of water or ethylene glycol in transmission fluid.
15-00-89-004G2024-05-15. Service bulletin. ENGINE; SUSPENSION; POWER TRAIN. This service bulletin provides technicians with information to help identify the differences between what is considered a fluid leak, and what is considered fluid seepage.
22-NA-2232024-03-19. Service bulletin. POWER TRAIN. This informational bulletin advises the tech of a possible wrong fluid used when performing a maintenance or repair to the rear axle.
PI1394B2024-02-02. Service bulletin. POWER TRAIN; ENGINE AND ENGINE COOLING. This PI bulletin advises the technician on the proper way to install the pistons in an engine.
22-NA-2232023-11-29. Service bulletin. EQUIPMENT; POWER TRAIN. This informational bulletin advises the tech of a possible wrong fluid used when performing a maintenance or repair to the rear axle.
03-00-91-001I2023-11-22. Service bulletin. WHEELS; POWER TRAIN; STEERING; SUSPENSION; ENGINE AND ENGINE COOLING. This service bulletin provides a vibration analysis worksheet the technician can use in conjunction with the appropriate Vibration Analysis-Road testing procedure when diagnosing vibration concerns.
23-NA-1532023-09-26. Service bulletin. ENGINE AND ENGINE COOLING; POWER TRAIN. The service bulletin advises the tech of a normal transmission shift condition and the delay in throttle response when the throttle plate is opened rapidly and advises the customer that it is normal for the delay.
15-00-89-004F2023-09-08. Service bulletin. STEERING; SUSPENSION; ENGINE AND ENGINE COOLING; POWER TRAIN. This service bulletin provides technicians with updated information to help identify the differences between what is considered a fluid leak, and what is considered fluid seepage.
17-NA-0662023-07-25. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION; POWER TRAIN. This service bulletin provides information for automatic transmission Oil Cooler Flush and flow test.
17-NA-0662023-07-13. Service bulletin. POWER TRAIN. This service bulletin provides information for automatic transmission Oil Cooler Flush and flow test.
08-07-30-035G2023-04-22. Service bulletin. POWER TRAIN. This bulletin provides information on the harmful effects of water or ethylene glycol in transmission fluid.
99-04-20-002N2023-03-03. Service bulletin. POWER TRAIN. This service bulletin provides information on Driveline Clunk Noise and what is acceptable and what is considered normal operation.
N2223808402022-11-17. Service bulletin. POWER TRAIN:AUTOMATIC TRANSMISSION. 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.
22-NA-2232022-11-09. Service bulletin. POWER TRAIN. This informational bulletin advises the tech of a possible wrong fluid used when performing a maintenance or repair to the rear axle.
15-00-89-004E2022-10-11. Service bulletin. POWER TRAIN; SUSPENSION; ENGINE AND ENGINE COOLING; SERVICE BRAKES, HYDRAULIC; STEERING. This service bulletin provides technicians with updated information to help identify the differences between what is considered a fluid leak, and what is considered fluid seepage.
06-00-89-031H2022-10-11. Service bulletin. POWER TRAIN; ENGINE AND ENGINE COOLING. This service bulletin provides information on OEM and Remanufactured Engine and Automatic Transmission/Transaxle Identification.

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