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Service bulletin 23-NA-156

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 id10245581
Published by NHTSA2023-11-30
Manufacturer's number23-NA-156
Manufacturer's date2023-11-15
NHTSA componentPOWER TRAIN

NHTSA's summary

This service bulletin informs the technician on the running changes to the M1L automatic transmission.

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

Vehicles listed
CHEVROLET CORVETTE2020, 2021, 2022, 2023, 2024

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

Recalls for the same vehicles and component
22V0910002022-02-17. POWER TRAIN:DRIVELINE:DRIVESHAFT

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
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.
23-NA-1562025-04-28. Service bulletin. This service bulletin informs the technician on the running changes to the M1L, M1M and MLH automatic transmission.
21-NA-0492025-01-30. Service bulletin. This service bulletin provides a Diagnostic Aid for PicoScope Information and Setup for Transmission Related Concerns.
24-NA-2732025-01-24. Service bulletin. This service bulletin provides a procedure to replace the Drive Motor Disconnect Clutch Actuator to correct a customer concern of a Malfunction Indicator Lamp (MIL) with DTC U01BE.
09-06-04-026Z2025-01-23. Service bulletin. This bulletin provides information on identifying Non-GM Engine Calibrations for Gasoline Engines using the Tech 2 or GDS 2.
24-NA-0252025-01-23. Service bulletin. This service bulletin provides information to correct a customer concern of Check Engine Light or Malfunction Indicator Lamp Illuminated with DTCs U0401 and/or U1611 Set.
23-NA-1562025-01-16. Service bulletin. This service bulletin informs the technician on the running changes to the M1L, M1M, MLH automatic transmissions.
08-07-30-035I2024-12-19. Service bulletin. This service bulletin provides information on the harmful effects of ethylene glycol in transmission fluid.
24-NA-0252024-12-19. Service bulletin. This service bulletin provides information to correct a customer concern of Check Engine Light or Malfunction Indicator Lamp Illuminated with DTCs U0401 and/or U1611 Set.
PIP60262024-12-09. Service bulletin. This Preliminary Information communication advises the technician on the need to provide additional information when creating a TAC case for a DCT transmission