# Service bulletin KC\-55

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.

- Type: Service bulletin
- NHTSA id: 10203988
- Published by NHTSA: 2021\-12\-07
- Manufacturer's number: KC\-55
- Manufacturer's date: 2021\-11\-17
- NHTSA component: POWER TRAIN

## NHTSA's summary

Automated Manual Transmission \( AMT \- F \) \( I\-Shift, mDRIVE \) Clutch Valve Unit \( CVU \) Makes Intermittent Buzzing Noise With The Key On And Engine Off

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2021/MC-10203988-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2021/MC-10203988-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Transmission and driveline

## Vehicles listed

- MACK MACK

JSON: [/v1/bulletins/10203988](/v1/bulletins/10203988)

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