Originally Posted by Ken Fichtner

Document ID# 1982105

Subject: Intermittent Spongy Clutch Pedal Sticking To The Floor During Hard Acceleration And High RPM Shifts - keywords contaminate fluid hydraulic #PIP4145 - (06/04/2007)

Models: 2005-2007 Chevrolet Corvette, Corvette Z06 Equipped with a Tremec 6-speed Transmission RPO MM6, MZ6

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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Some customers may comment about an intermittent spongy clutch pedal feel or clutch pedal sticking to the floor. This may be aggravated by aggressive driving and high clutch operating temperatures. Higher than expected levels of water in the clutch fluid greater than 2% may cause the clutch fluid to boil. The presence of water in the fluid lowers the boiling point significantly; when these conditions are present the driver may lose customary clutch pedal feel and performance.

Recommendation/Instructions:
If the above condition is intermittent flush the hydraulic system using DOT 4 fluid part number 88958860 (88901244 in Canada), prior to replacement of any mechanical or hydraulic components.

To eliminate the opportunity for moisture to enter the clutch hydraulic system.

The clutch fluid level inspection should be a VISUAL inspection only. Look through the transparent reservoir and observe the fluid level. Avoid removing the cap. Do not remove the cap just to top-off clutch fluid. Leave the system closed and sealed. During PDI inspection or routine servicing the cap should not be opened for just an inspection.
DOT 4 clutch fluid has a 2 week shelf life. Do not use fluid if container opening date is unknown or older than 2 weeks. Do not mix or re-use old fluid. Current service information already covers the issue of reuse.
To provide the best clutch operation, it is recommended that the owner change the clutch fluid every 2 calendar years. Please flush and replace the clutch fluid with P/N 88958860 (88901244 in Canada) or equivalent DOT 4.
The current service information and owners manual will be updated to reflect this information.

Note: If the concern is not intermittent, inspect clutch hydraulic system for leaks and repair as necessary after repairs are completed flush system with DOT 4 fluid part number 88958860 (88901244 in Canada).

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

Originally Posted by dailydriver

THANKS, Ranger. But a 2 WEEK shelf life! You mean to tell me that I can spend $85.00 on a liter of Castrol SRF and I have to dump it after 14 days, even with the cap on tight, stored in a dry place with a bid bag of desicant, sealed in a zip lock, if I have any left over??!!!!?
WOW! Now I know why you use the cheapo stuff, even in your "exotic".

Originally Posted by UMD_Jesse

about the two week shelf life, Ive read somewhere that this is only when the fluid is stored in a plastic container...the plastic container is sealed under some kind of pressure that prevents it from leaking, but once you open it the plastic can "breath" and moisture in the air will get in through the plastic, regardless of how tight the cap is on. If the fluid is in a metal container, I think it keeps for longer, after its opened.

Originally Posted by LilJayV10

Ranger,

I read your thread about clutch fluid a few weeks ago. I had my clutch pedal stick on the floor the other day after putting down about 40 ft of black marks on the pavement. I thought my clutch was going out for sure. After I drive the car hard for a while the clutch pedal starts to feel spongy. When I changed my oil last night I looked at the clutch fluid. It looks as dark as my oil does. I guess it's time to flush it. I think i am going with the LS7 clutch. The car has 30,xxx miles on it, but the guy that had before me had drag radials on it. I might flush the fluid first and see how it acts.

Originally Posted by Ranger

My advice is to get your clutch fluid clean, really clean, and then keep it that way. Doing that will probably solve your pedal issue. But it's an ongoing PM routine, not a one-time fix.

As for the changing the clutch, would suggest not changing unless the current one is slipping.

Ranger