Clutch Pedal Does Not Return to Up Position During Shifts at High Engine RPMs (Inspect Date Code and Replace Clutch Kit)

This bulletin is being revised to add the RPO MZ6 6-Speed Manual Transmission. Please discard Corporate Bulletin Number 05-07-31-001 (Section 07 - Transmission/Transaxle).

Some customers may comment that while shifting at engine speeds greater then 6000 RPMs, the clutch pedal does not return to the up position. As the engine speed decreases, the clutch pedal will return to the up position.

It is possible that when the engine speed is greater than 6000 RPM and the clutch pedal is depressed, centrifugal loads on the clutch diaphragm spring may be greater than the clutch return load from the diaphragm spring. This force created by RPM would be directionally opposite to the clutch bearing force, causing a near net zero or less than zero return force. As a consequence, the clutch pedal may be stuck at the bottom of travel at the floor. Once the engine speed reduces to less than 6000 RPM, spring return load dominates and the clutch pedal returns to normal function.

Inspect the clutch date code and replace the clutch kit if built PRIOR to the following date code:

1. Remove the transmission to inspect the date code on the clutch pressure plate (4). Refer to the applicable procedure below:

•	Corvette -- Clutch Assembly Replacement (SI Document ID #1399532)

•	CTS-V -- Clutch Assembly Replacement (CTS-V) (Document ID #1453054)

•	SSR -- Clutch Assembly Replacement (SI Document ID #1581481)





Important: 

The suspect clutches were built PRIOR to the following date codes:

•	4M21A/B/C for CTS-V and SSR

•	4M13A/B/C for Corvette

2. The date code is located on the pressure plate cover as shown above.
3. Replace the clutch kit (see part list below) if the date code on the pressure plate is PRIOR to the following date code:

•	4M21A/B/C for CTS-V and SSR

•	4M13A/B/C for Corvette

The date codes are interpreted as follows:

•	The first character is the year.

-

4 = 2004

-

5 = 2005

•	The second character is the build month.

Important: The letter J is not used in the month code.

-	January = A

-	February = B

-

March = C

-

April = D

-

May = E

-

June = F

-

July = G

-	August = H

-	September = I

-	October = K

-	November = L

-	December =M

•	The third character is the day of the month.

Important: It is possible that the fourth digit, the shift code, may not be present on the date code. The shift code does not play a critical part in determining a suspect clutch kit.

•	The fourth, and final, character is the shift code = A/B/C.

For vehicles repaired under warranty, use: