Information on 9TH Gear Operation – 2018-2023 Buick Cadillac Chevrolet GMC

Chevrolet Buick GMC Cadillac

NHTSA ID Number: 10219391 Manufacturer Communication Number: 21-NA-181 Summary This service bulletin provides 9th gear operation information to respond to customers that may comment on transmission shift operation.   Condition Some customers may comment that the transmission doesn’t shift into 9th gear or maintain 9th gear operation to customer expectations.   Information The GM 9-speed transmission does …

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