Chevrolet Corvette 2020–2025 — technical service bulletin
Bulletin 23-NA-156 · NHTSA communication 11017254 · issued Mar 28, 2025
Technical service bulletin
communication type
Power Train
component
2020–2025
model years
6
vehicle entries
Official summary
This service bulletin informs the technician on the running changes to the M1L, M1M and MLH automatic transmission.
Vehicles covered
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.